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Fri, 26 Feb 2021 00:00:00 +0000

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Content Registration

Support for Reference Linking

Amanda Bartell — Fri, 15 Aug 2025 00:00:00 +0000

Reference linking enables researchers to follow a link from the reference list to other full-text documents, helping them to make connections and discover new things.

Reference Linking means including Crossref DOIs (displayed as URLs) in the reference lists that you provide in your own published work. This enables researchers to follow a link from a reference list to the current landing page for that referenced work. And because it’s a DOI rather than just a link, it will remain persistent.

So, instead of just including the reference in your reference list…

Soleimani N, Mohabati Mobarez A, Farhangi B. Cloning, expression and purification flagellar sheath adhesion of Helicobacter pylori in Escherichia coli host as a vaccination target. Clin Exp Vaccine Res. 2016 Jan;5(1):19-25.

…you should also display the DOI link:

Soleimani N, Mohabati Mobarez A, Farhangi B. Cloning, expression and purification flagellar sheath adhesion of Helicobacter pylori in Escherichia coli host as a vaccination target. Clin Exp Vaccine Res. 2016 Jan;5(1):19-25. https://doi.org/10.7774/cevr.2016.5.1.19

Because Crossref is all about rallying the scholarly community to work together, reference linking is an obligation for all Crossref members. But you don’t have to be a Crossref member to link your references - we provide free tools that anyone can use to match their reference lists to existing DOIs so they can link their references.

Watch the introductory reference linking animation in your language:

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How Reference Linking works

Download the reference linking factsheet, and explore factsheets for other Crossref services and in different languages.

Benefits of reference linking

Persistent links enhance scholarly communications. Reference linking offers important benefits:

Reciprocity: members’ records are linked together and more discoverable because all members link their references. As a member organisation, we can obligate all our members to link their references, so that individual members can avoid the inconvenience of signing bilateral agreements to link to persistent resources on other platforms. The result is a scholarly communications infrastructure that enables the exchange of ideas and knowledge.
Discoverability: research travels further when everyone links their references. Because DOIs don’t break if implemented correctly, they will always lead readers to the resource they’re looking for, including yours. When the DOIs are displayed, anyone can copy and share them. This will also enable better tracking of where and when people are talking about and sharing scholarly objects, including in social media.

Obligations and fees for reference linking

Reference Linking is an obligation of membership for all Crossref members. But anyone can use our support tools for Reference Linking - you don’t have to be a member. And there’s no charge to use our support tools for Reference Linking.

Getting started with reference linking

There are various different ways to look up other member’s DOIs to add to your reference lists. Read more here.

Important note: Reference Linking is not the same as including your reference lists in your metadata record. Here’s more information about how to add your reference lists to your metadata records.

Best practice for reference linking

Start reference linking within 18 months of joining Crossref
Link references for back-year as well as current resources
Link references in all relevant resource types such as preprints, books, data, conference proceedings, etc.
Make sure the links in your references and other platforms conform to our DOI display guidelines

Grant Linking System (GLS)

Rocío Gaudioso Pedraza — Wed, 04 Sep 2024 00:00:00 +0000

The Crossref Grant Linking System (GLS) is a service for research funders to contribute to open science infrastructure. As members of Crossref, funders create unique links and open metadata about their support of all kinds, from financial grants to prizes to use of facilities. This metadata is distributed at scale openly and globally and the unique links are acknowledged in any outputs of the funding, such as publications, preprints, data and code - in order to streamline the reporting process.

Background to the Grant Linking System

In 2017, our board agreed that connecting more intentionally with research funding should be a key strategic priority for the Crossref infrastructure which already supported all kinds of research outputs like articles, preprints, standards, datasets, etc. Whilst the scholarly community has long been linking persistently between articles and other objects (Crossref), people (ORCID), and institutions (ROR), the record of the award was not captured in a consistent way across funders worldwide. Researchers and publishers have long been acknowledging funders in their publication metadata but the grants themselves were not easily and persistently linked up with the literature or with researchers or with institutions.

After a board motion in 2017, we reconvened our Funder Advisory Group and worked with other community partners such as Europe PMC to create a new strategic plan. Part of that work was to agree on a sustainability model and fee schedule, and to design a schema that would capture relevant metadata about grants and projects, and in 2019 we launched the Crossref Grant Linking System (GLS).

Now, over 35 funders have joined as members of Crossref created over 125,000 grants with metadata records and globally unique persistent links that can be connected with outputs, activities, people, and organisations.

Features of the Grant Linking System

Globally unique persistent link and identifier for each grant
Connected with over 170 million published outputs
Funder-designed metadata schema, including project, investigator, value, and award-type information
Programmatic or no-code methods to send metadata
- Thanks to the Gordon and Betty Moore Foundation who funded development of the online grant registration form in 2023.
Distributed openly to thousands of tools and services
Open search and API for all to discover funding outcomes
Crossref-hosted landing pages
A global community of ~50 funder advisors and >35+ funders already in the Grant Linking System
Membership of Crossref; influence the foundational infrastructure powering open research

What our GLS funder members say

Research funders are a part of the scholarly communications system. We not only provide the funding to do the actual research but can also be the authoritative source of data about the projects we have funded and the outputs arising from that funding. Increasingly, all these elements – grants, researchers, outputs - are linked with persistent identifiers to ensure that research is findable and accessible. As part of its open science policy, NWO will start participating in the Crossref Grant Linking System from July 2025

– Hans de Jonge, Director of Open Science NL, part of the Dutch Research Council (NWO)

Grant DOIs enhance the discovery and accessibility of funded project information and are one of the important links in a connected research ecosystem. I’m grateful and proud to contribute to the robustness and interconnectedness of the research infrastructure. Few funders are currently participating in the Crossref Grant Linking System, and I encourage others to consider doing so. This adoption follows the “network effect,” where the value and utility increase as more people participate, encouraging even wider adoption.

– Kristin Eldon Whylly, Senior Grants Manager and Change Management Lead at Templeton World Charity Fund (TWCF)

The initiative by FCT to assign unique DOIs to national public funding through Crossref is a game-changer for open science, linking funding directly to scientific outcomes and boosting transparency. Join us in this effort—let’s make every grant count and ensure open access to research information!"

– Cátia Laranjeira, PTCRIS Program Manager at Fundacao para a Ciencia e a Tecnologis (FCT Portugal)

+- Benefits for funders

During research management (primarily coming from activity reporting):

Improved analytics and data quality
More complete picture of outputs and impact
Better value from investments in reporting services
Improved timeliness, completeness and accuracy of reporting
More complete information to support analysis and evaluation
Streamlined discovery of funded content

During reporting and evaluation (with a special component for policy compliance):

Better information about publication pathways and policy compliance
Better/more comprehensive data about the impact and outcomes of their policies
Improved data on policy compliance
Improved data on policy progress and impact
Streamlined discovery of funded content
Better understanding of the effects of investments on the research landscape
Clearer data on impact and ‘ROI’ for facility/infrastructure investments
Improved analysis and evidence of outcomes of career support
Improved publication ethics and research integrity (COIs, funding transparency etc.)
Improved picture of long-term ROI and impact

+- Benefits for content hosts

Content hosts include publishers, data repositories, and hosting platforms

Improved publication ethics and research integrity
Improved services to authors
Improved transparency on content access
More connections within and between platforms and content
New platform opportunities and value added services
Reduced administrative and information management/verification overhead
New value add services
Greater ecosystem integration
Improved user experiences

+- Benefits for research organisations

This includes benefits for research administrators and managers, resource managers, project managers, and institutional policy makers.

Research administrators and managers benefit from:

Opportunities to provide additional effective and constructive support for proposal preparation (pre-award)
Find it easier to perform due diligence (pre-award)
Reduced overhead in data collection (research management)
Reduced overhead in compliance and data checking (research management)
Reduced time/effort and improved data quality (reporting and evaluation)
Improved evidence for decision making (reporting and evaluation)
Better evidence for career and organisational impact (reporting and evaluation)

Resource managers benefit from:

Better intelligence on funding sources and dynamics (pre-award)
Better understanding of who is using their facilities (research management)
Clearer links to downstream benefits of their work and provision (reporting and evaluation)
Improved reporting/analysis capacity (reporting and evaluation)
Improved data quality (research management)
Simplified data sharing (research management)

Institutional policy makers and strategists benefit from:

Understanding funder portfolios to improve grant targeting (pre-award)
Reduced data gathering overhead and improved intelligence about their portfolio of outputs (research management)
Richer understandings of their research activity portfolio (research management)
Better management of APC budgets (research management)
Greater insight and evidence for stronger strategic planning (research management)
More complete information to support analysis and evaluation (reporting and evaluation)
Improved analytics and data quality (reporting and evaluation)
Better understanding of outcomes of studentships and postdoctoral positions (reporting and evaluation)
Improved connections to alumni (reporting and evaluation)
Better data for benchmarking (reporting and evaluation)

+- Benefits for researchers

In applying for funding, researchers benefit from:

Reduced data entry and improved reusability of information in applications
Better tailored institutional support
Improved targeting and design of career supporting interventions from funders
Improved review
Easier completion of applications

In conducting research, researchers can benefit from:

Boosted current awareness
Easier access to facilities
Reduced administrative overhead

In publishing researchers benefit as authors and as readers from:

Shorter publication delays
Simplified acknowledgement processes
Critical awareness of any potential bias
Richer context and simplified discovery
Reduced uncertainty and administration around policy compliance

In reporting on their activities to funders:

Improved reporting experiences
A shift from data collation/entry to verification
Easier acknowledgement of support for their careers

In building their careers:

Boosted impact and enhanced visibility
As collaborators, from better understanding of the contributions of others and improved recognition for their own contributions
Clearer, more complete and complex career records
Enhanced career recognition and support
More diverse data sources for recognition and reward

At every stage, the core benefits for researchers include:

Better career representations and reputational enhancement
Simplified administration, reporting and application processes with reduced overhead and duplication of effort
Better intelligence about research support and future opportunities for funding and collaboration

Funder-designed metadata model

One thing to note about Crossref grant records is that they can be registered for all sorts of support for research, such as awards, use of facilities, sponsorship, training, or salary awards. Essentially any form of support provided to a research group. The award type list (agreed by the Funder Advisory Group) is currently:

APC: article processing charge
award: a prize, award, or other type of general funding
BPC: book processing charge
contract: agreement involving payment
crowdfunding: funding raised via multiple sources, typically small amounts raised online
endowment: gift of money that will provide an income
equipment: use of or gift of equipment
facilities: use of location, equipment, or other resources
fellowship: grant given for research or study
grant: a monetary award

infrastructure: developmnet of infrastructure to support research
loan: money or other resource given in anticipation of repayment
other: award of undefined type
prize: an award given for achievement
salary-award: an award given as salary, includes intramural research funding
secondment: detachment of a person or resource for temporary assignment elsewhere
seed-funding: an investor invests capital in exchange for equity
training-grant: grant given for training

Take a look at the metadata schema described in our schema markup guide for grant metadata, to see the details of how to send (or retrieve) metadata including investigators, funding values and types, unlimited numbers of projects with titles and descriptions, and more.

Outcomes: funding and outputs connected

Matching and analyses

Over the years, since the Grant Linking System has evolved, we have been closely watching and analysing the effects of all funding data on the global Crossref infrastructure. This round-up of some of the community's analyses shows the breadth of applications.

In 2024, we updated some matching on award IDs in publications with grants registering in Crossref, really showing the linking system in effect.

number of	as of 2023-04-16	as of 2024-04-16
grants	76,621	120,819 (+58%)
members registering grants	28	34 (+21%)
matched relationships	98,593	155,475 (+58%)
matched grants	18,114	27,199 (+50%)

See earlier reports that show the same sort of analyses of grant<->output matching as the above table, and their results with more explanation, from 2023: The more the merrier, or how more registered grants means more relationships with outputs; and from 2022: Follow the money, or how to link grants to research outputs.

The role of publishers

Publishers have been including funding acknowledgements in their publication metadata at Crossref for over a decade. But they did not have a persistent link to allow seamless linking between article and grant. Now with the Crossref system they do - and as more and more funders join and register grants with us, more and more publishers will start to pick these up and include them in their article (and other) metadata. In fact, all 24,000 Crossref members have a responsibility to use Crossref links wherever they can, in reference lists, on interfaces, in search engines, etc.

Real life example from eLife<->Wellcome of the GLS in action

This unique Crossref link https://doi.org/10.7554/eLife.90959.3 is for an eLife article that displays another unique Crossref link (https://doi.org/10.35802/212242) to the Wellcome grant on the Europe PMC page.

The same example now in the metadata using the funder-designed metadata schema for relationship is-financed-by.

That’s an example of funders and their grants and publishers and their publications connecting together, using the Grant Linking System within the global open science infrastructure.

The role of Grant Management Systems

Following Europe PMC helping Wellcome and their other funders to create Crossref XML and host landing pages on their site, and Altum’s ProposalCentral integrating with Crossref since 2021, in 2024, the GLS started to see increased interest from other systems in integrating with Crossref. One such example is an open-source plugin for Fluxx, which was kindly funded by OA.Works: https://github.com/oaworks/create-grant-doi-in-fluxx.

We’re currently reviewing and supporting Crossref integrations within a number of other Grant Management Systems and will add a list of those integrations here soon. Please get in touch if you are able to contribute to this work.

Getting started

If you’re reading this far you must be about ready to get going. You’ll be joining Wellcome, European Research Council, NWO - Dutch Research Council, FWF - Austrian Science Fund, FCT - Foundation for Science and Technology, Portugal, JST - Japan Science and Technology Agency, CSIRO, Melanoma Research Alliance, OSTI at the US Department of Energy, and many other Crossref funder members.

You will need to be a Crossref member in order to participate in the Grant Linking System and register unique links for your grants.

Once you’re a member (or in preparation for becoming one), take a look at our documentation on registering grants which will walk you through what you need to know and what information you can to send to Crossref (which makes it globally and openly distributed at scale through our APIs). Some things you will need:

Unique landing page for each grant, which should always also display the unique link
An Open Funder Registry ID (find yours by searching for your organisation at search.crossref.org/funding) and noting the ID in the URL (or ask us)
Ability to create and send XML metadata OR allocate staff to register using the manual form funded by the Moore Foundation
Map your internal award types to the Crossref award types
Create communications for your awardees and/or include the Grant Linking System in your agreements. We’ve compiled a few examples below.

Membership & fees

Funders who would like to participate in the Grant Linking System and register their research grants should apply to join as a member. In some cases, your organisation may already be a member - so we’ll check on that for you as you may be able to register grants under you existing membership. Membership comes with obligations to maintain the metadata record for the long term; our membership terms sets these out. You will also be able to participate in Crossref governance such as voting in or standing for our annual board elections - it’s very much encouraged to maintain funder voices in the oversight of Crossref. Your first year’s membership invoice needs to be settled before a DOI prefix is assigned and your grant registrations can begin.

Our current fee structure for funders includes an annual membership fee (from USD $200 to USD $1200 depending on annual award value) and a higher per record fee of USD $1.00 for current grants. During 2026 and 2027, we are also piloting a waiver of fees for historical grants (those older than two full calendar years). The membership fees were proposed by the original Advisory Group of funders and approved by the board in 2018, and the registration fees were revised last December. Please see our fees page for more information. Please note that fees are currently subject to our community consultation as part of the Resourcing Crossref for Future Sustainability (RCFS) Program that started in 2024.

Communicating with grantees

Some of our members have shared their standard notifications with the rest of the funder group. Some funders include mention of the Crossref unique link in their contracts, on acceptance, and some in emailed or online guidance. Some specify how the awardee should acknowledge their funding. We’ve noted a few examples that can be adapted depending on your process:

In an email notification

Dear [principal investigator],

Through Crossref, [funder name] has assigned a globally unique identifier to your grant: https://doi.org/10.#####/#####. We ask that this link is used in all instances when referencing our funding such as when submitting a journal article, or when posting other elements of your research (e.g. preprints, data). Please enter this unique identifier link in the Award Number field (or equivalent) if one is available, and in the funding acknowledgement section of your work (sample included). The publisher can then collect it and associate it with your work.

This will help to accurately identify and recognize any funding you have received, connect your research outputs with the grant automatically, streamline the reporting process, track the outputs of the grant. It can also boost the impact of your research and demonstrate your accomplishments to other funders and the rest of the research community.

Please use the following text to acknowledge the funding: “This publication is based on research supported by [funder name] (open funder registry ID ##########) under the grant https://doi.org/10.#####/#####”.

Further details are available […link to guidance as relevant].

In an agreement

Communications clause: Any publication based on or developed under the Grant must, unless otherwise requested by the Grantor, contain an acknowledgment in the following or similar language that includes the Grantor’s open funder registry identifier and the Grant digital object identifier (DOI): “This publication is based on research supported by [funder name] (open funder registry ID ##########) under the grant https://doi.org/10.#####/#####".

Acknowledgements

In mid-2024, we celebrated five years of grant linking! While thanks certainly go to our current volunteers from the funding community, we acknowledge that the GLS would not have been possible without early dedicated time and input from the following people and organisations on our working groups for governance and fees, and for metadata modelling:

Yasushi Ogasaka and Ritsuko Nakajima, Japan Science & Technology Agency
Neil Thakur and Brian Haugen, US National Institutes of Health
Jo McEntyre and Michael Parkin, Europe PMC
Robert Kiley and Nina Frentop, Wellcome
Alexis-Michel Mugabushaka and Diego Chialva, European Research Council
Lance Vowell and Carly Robinson, OSTI/US Dept of Energy
Ashley Moore and Kevin Dolby, UKRI/Medical Research Council/Research Councils UK
Salvo da Rosa, Children’s Tumor Foundation
Trisha Cruse, DataCite

Please contact our membership specialists with any questions about joining, or our technical support specialists with questions about the grants schema or how to register your grants.

Metadata Retrieval

Martyn Rittman — Sat, 03 Feb 2024 00:00:00 +0000

Analyse Crossref metadata to inform and understand research

Crossref is the sustainable source of community-owned scholarly metadata and is relied upon by thousands of systems across the research ecosystem and the globe.

Some of the typical users (outer) and uses (inner) of Crossref metadata

People using Crossref metadata need it for all sorts of reasons including metaresearch (researchers studying research itself such as through bibliometric analyses), publishing trends (such as finding works from an individual author or reviewer), or incorporation into specific databases (such as for discovery and search or in subject-specific repositories), and many more detailed use cases.

All Crossref metadata is open and available for reuse without restriction. Our 170 million records include information about research objects like articles, grants and awards, preprints, conference papers, book chapters, datasets, and more. The information covers elements like titles, contributors, descriptions, dates, references, connecting identifiers such as Crossref DOIs, ROR IDs and ORCID iDs, together with all sorts of metadata that helps to determine provenance, trust, and reusability—such as funding, clinical trial, and license information.

Take a look at a list of some of the organisations who rely on our REST API and read some of the case studies from a selection of users. Download the metadata retrieval fact sheet or read more about the types of metadata and records we have.

Anyone can retrieve and use >170 million records without restriction. So there are no fees to use the metadata but if you really rely on it then you might like to sign up for Metadata Plus which offers greater predictability, higher rate limits, monthly data dumps in XML and JSON, and access to dedicated support from our team.

Options for retrieving metadata

All Crossref metadata is completely open and available to all. Whatever your experience with metadata, there are several tools, techniques, and support guides to help—whether you’re just beginning, exploring occasionally, or need an ongoing reliable integration.

BEGINNING?

You’ve heard Crossref metadata might be useful and want to know where to start.

We recommend you start with metadata search, funder search, or simple text query for matching references to DOIs. Also take a look at the REST API which only needs you to get a JSON plugin to view the results. We are building tutorials to demonstrate the possibilities, starting with a Python notebook and an R notebook. If it’s retractions and corrections that you need, check out the frequently-updated csv file of the Retraction Watch dataset that we acquired and opened in 2023.

EXPLORING?

You have some specific queries and want a lightweight way to use Crossref metadata.

Take a look at the in-depth documentation for our REST API on this site and try it out at api.crossref.org, including tips for how to get the most from our metadata. If you’re comfortable with tar data files you can download our latest annual public data file. Our Crossref Learning Hub is also another helpful resource.

INTEGRATING?

You rely on Crossref metadata and need to incorporate it into your product at scale.

You might want to jump straight to subscribing to Metadata Plus, which is our premium service for the REST API that comes with monthly data dumps in JSON and XML, higher rate limits, and fast support. But we always recommend that you try out the public version first to make sure it will work for your product. If you’re looking for a single DOI record in multiple formats (e.g. RDF, BibTex, CSL) you can use content negotiation.

Watch the animated introduction to metadata retrieval

English 한국어 Japanese Chinese Español Français Bahasa Indonesia العربية Português do Brasil

Learn more by visiting our learning hub.

Cited-by

Tue, 09 Feb 2021 00:00:00 +0000

Cited-by supports members who display citations, enabling the community to discover connections between research outputs.

Scholars use citations to critique and build on existing research, acknowledging the contributions of others. Members can include references in their metadata deposits which Crossref uses to create links between works that cite each other. The number of citations each work receives is visible to anyone through our public APIs. Through our Cited-by service, members who deposit reference metadata can retrieve everything they need to display citations on their website.

Members who use this service are helping readers to:

easily navigate to related research,
see how the work has been received by the wider community,
explore how ideas evolve over time by highlighting connections between works.

Watch the introductory Cited-by animation in your language:

English 한국어 Japanese Chinese Español Français Bahasa Indonesia العربية 한국어 Português do Brasil

How Cited-by works

Cited-by begins with references deposited as part of the metadata records for your content. Learn more about depositing references.

A member registers content for a work, the citing paper. This metadata deposit includes the reference list. Crossref automatically checks these references for matches to other registered content. If this is successful, a relationship between the two works is created. Crossref logs these relationships and updates the citation counts for each work. You can retrieve citation counts through our public APIs.

Members can use the Cited-by service to retrieve the full list of citing works, along with all the bibliographic details needed to display them on their website.

Note that citations from Crossref may differ from those provided by other services because we only look for links between Crossref-registered works and don’t share the same method to find matches.

Obligations and fees for Cited-by

Participation in Cited-by is optional, but encouraged.
There is no charge for Cited-by.
Depositing references is not a requirement, but strongly encouraged if you are using Cited-by.

Best practice for Cited-by

Because citations can happen at any time, Cited-by links must be kept up-to-date. Members should either check regularly for new citations or (if performing XML queries) set the alert attribute to true. This means the search will be saved in the system and you’ll get an alert when there is a new match.

Depositing your own references is strongly encouraged if you use Cited-by. If you don’t, the citations you retrieve will not include those from your own works. This is likely to lead to under-reporting of citations counts by at least 20% and you are missing the opportunity to point readers to other similar works on your platform.

Download the Cited-by factsheet, and explore factsheets for other Crossref services and in different languages.

How to access citation matches

Members who deposit references allow them to be retrieved by anyone using our public APIs. For example:

http://api.crossref.org/works?filter=has-references:true

Also in the metadata is the number of citations a work has received, under the tag "is-referenced-by-count".

To retrieve the full list of citations you need be a member using Cited-by. While anyone can use an API query to see the number of citations a work has received, members can retrieve a full list of citing DOIs and callback notifications informing them when one of their works has been cited. Details of the citing works can be displayed on your website alongside the article.

Getting started with Cited-by

Learn more about Cited-by in our documentation.

Content Registration

Sara Bowman — Wed, 08 Apr 2020 00:00:00 +0000

Content Registration allows members to register and update metadata via machine or human interfaces.

When you join Crossref as a member you are issued a DOI prefix. You combine this with a suffix of your choice to create a DOI, which becomes active once registered with Crossref. Content Registration allows members to register a DOI and deposit or update its associated metadata, via machine or human interfaces.

Benefits of content registration

Academic and professional research travels further if it’s linked to the millions of other published papers. Crossref members register content with us to let the world know it exists, instead of creating thousands of bilateral agreements.

Members send information called metadata to us. Metadata includes fields like dates, titles, authors, affiliations, funders, and online location. Each metadata record includes a persistent identifier called a digital object identifier (DOI) that stays with the work even if it moves websites. Though the DOI doesn’t change, its associated metadata is kept up-to-date by the owner of the record.

Richer metadata makes content useful and easier to find. Through Crossref, members are distributing their metadata downstream, making it available to numerous systems and organisations that together help credit and cite the work, report impact of funding, track outcomes and activity, and more.

Members maintain and update metadata long-term, telling us if content moves to a new website, and they include more information as time goes on. This means that there is a growing chance that content is found, cited, linked to, included in assessment, and used by other researchers.

Participation Reports give a clear picture for anyone to see the metadata Crossref has. See for yourself where the gaps are, and what our members could improve upon. Understand best practice through seeing what others are doing, and learn how to level-up.

This is Crossref infrastructure. You can’t see infrastructure, yet research—and researchers all over the world—rely on it.

Download the content registration factsheet, and explore factsheets for other Crossref services and in different languages.

How content registration works

To register content with Crossref, you need to be a member. You’ll use one of our content registration methods to give us metadata about your content. Note that you don’t send us the content itself - you create a metadata record that links persistently (via a persistent identifier) to the content on your site or hosting platform. Learn more about metadata, constructing your DOIs, and ways to register your content.

You should assign Crossref DOIs to and register content for anything that is likely to be cited in the scholarly literature.

No matter whether you register content using one of our helper tools, or creating your own metadata files, all metadata deposited with Crossref is submitted as XML, and formatted using our metadata deposit schema section. Explore our XML sample files to help you create your own XML.

What types of resources and records can be registered with Crossref?

We are working to make our input schema more flexible so that almost any type of object can be registered and distributed openly through Crossref. At the moment, members tend to register the following:

Books, chapters, and reference works: includes book title and/or chapter-level records. Books can be registered as a monograph, series, or set.
Conference proceedings: information about a single conference and records for each conference paper/proceeding.
Datasets: includes database records or collections.
Dissertations: includes single dissertations and theses, but not collections.
Grants: includes both direct funding and other types of support such as the use of equipment and facilities.
Journals and articles: at the journal title and article level, and includes supplemental materials as components.
Peer reviews: any number of reviews, reports, or comments attached to any other work that has been registered with Crossref.
Pending publications: a temporary placeholder record with minimal metadata, often used for embargoed work where a DOI needs to be shared before the full content is made available online.
Preprints and posted content: includes preprints, eprints, working papers, reports, and other types of content that has been posted but not formally published.
Reports and working papers: this includes content that is published and likely has an ISSN.
Standards: includes publications from standards organisations.
You can also establish relationships between different research objects (such as preprints, translations, and datasets) in your metadata.

Learn more about all the metadata that can be included in these records with our schema library and markup guides.

Obligations and fees for content registration

You pay a one-time content registration fee for each content item you register with us. content registration fees are different for different types of content and sometimes include discounts for back-year material. You don’t pay to update an existing metadata record. It’s an obligation of membership that you maintain your metadata for the long term, including updating any URLs that change. In addition, we warmly encourage you to correct and add to your metadata, and there is no charge for redepositing (updating) existing metadata. Learn more about maintaining your metadata, and managing existing DOIs.

Your content registration fees are billed quarterly in arrears. This means you’ll usually receive a bill at the beginning of each quarter for the content you registered in the previous quarter. The only exception is if you’ve only registered a small number of DOIs.

Getting started with content registration

Learn more about content registration in our documentation.

Crossmark

Lena Stoll — Wed, 08 Apr 2020 00:00:00 +0000

The Crossmark button gives readers quick and easy access to the current status of an item of content, including any corrections, retractions, or updates to that record.

Crossmark provides a cross-platform way for readers to quickly discover the status of a research output along with additional metadata related to the editorial process. Crucially, the Crossmark button can also be embedded in PDFs, which means that members have a way of alerting readers to changes months or even years after it’s been downloaded.

Research doesn’t stand still: even after publication, articles can be updated with supplementary data or corrections. It’s important to know if the content being cited has been updated, corrected, or retracted. Crossmark makes this information more visible to readers. With one click, you can see if content has changed, and access valuable additional metadata provided by the member, such as key publication dates (submission, revision, acceptance), plagiarism screening status, and information about licenses, handling editors, and peer review.

Crossmark lets readers know when a substantial change affecting the citation or interpretation has occurred, and that the member has updated the metadata record to reflect the new status.

Watch the introductory Crossmark animation in your language:

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Benefits of Crossmark

Members can report updates to readers and showcase additional metadata.
Researchers and librarians can easily see the changes to the content they are reading, which licenses apply to the content, see linked clinical trials, and more.
Anyone can access metadata associated with Crossmark through our REST API, providing a myriad of opportunities for integration with other systems and analysis of changes to the scholarly record.

How Crossmark works

Members place the Crossmark button close to the title of an item on their web pages and in PDFs. They commit to informing us if there is an update such as a correction or retraction, as well as optionally providing additional metadata about editorial procedures and practices.

While members who implement Crossmark provide links to update policies and commit themselves to accurately reporting updates, the presence of Crossmark itself is not a guarantee. However, it allows the community to more easily verify how members are updating their content.

If you use Crossmark, the Crossmark button must be applied to all of your new content, not just content is updated. Selective implementation means that a reader, such as a research or librarian, who downloaded a PDF version before the update would have no way to know that it has been updated. We also encourage you to implement Crossmark for back-year records, although doing so is optional. At least, we encourage you to do so for back-year records that have been updated.

Obligations for Crossmark

Any member can provide update metadata and register an update policy. If you are a member who implements the Crossmark button, you must:

Maintain your content and promptly register any updates.
Include the Crossmark button on all digital formats (HTML, PDF, ePub).
Implement Crossmark using the script provided by us.
Not alter the Crossmark button in any way other than adjusting its size.

Implementing the Crossmark button involves technical changes to your website and production processes. Check that you have the necessarily expertise to implement these before you start. If not, you can start to deliver update metadata and implement the Crossmark button at a later point.

Any organisation can also implement the Crossmark button on pages where they display content. If you do so, you must follow the guidelines above, except for the first point if you are not reponsible for the content.

There are no additional fees to participate in Crossmark.

How to participate in Crossmark

There are several steps for members to fully implement Crossmark:

Devise an update policy, assign it a DOI, and register it with us.
Add the update policy and, optionally, other relevant metadata to your metadata records.
Publish corrections, retractions, and other updates for works where necessary, and register their metadata. See our guidance on registering updates.
Implement the Crossmark button online and in PDFs.

Learn more about participating in Crossmark.

To see which Crossref members are registering Crossmark information, visit Participation Reports. These reports give a clear picture for anyone to see the metadata Crossref has including Crossmark data.

Learn more about version control, corrections, and retractions.

Download the Crossmark factsheet, and explore factsheets for other Crossref services and in different languages.

Getting started with Crossmark

Learn more about Crossmark in our documentation.

Open Funder Registry (OFR)

Lena Stoll — Wed, 08 Apr 2020 00:00:00 +0000

The Open Funder Registry (OFR, formerly FundRef) and associated funding metadata allows everyone to have transparency into research funding and its outcomes. It’s an open and unique registry of persistent identifiers for grant-giving organisations around the world.

It is good practice for authors to acknowledge support for and contributions to their research in their published articles. This support may be financial, such as a grant or salary award; or practical, such as the use or loan of specialist facilities and equipment. They do this by listing the funding agency and the grant number somewhere in their article - usually the first or last page, or in the acknowledgments or footnotes section. Members contribute by depositing the funding acknowledgements from their publications as part of their standard metadata, together with the unique funder IDs listed in the OFR. The deposit should include funder names, funder IDs, and associated grant numbers.

This means that anyone can make connections, for example, to identify which funders invest in certain fields of research. Funding data is also used by funders to track the publications that result from their grants.

The Crossref OFR is an open registry of grant-giving organisation names and identifiers, which you use to find funder IDs and include them as part of your metadata deposits. It is a freely-downloadable RDF file. It is CC0-licensed and available to integrate with your own systems. Funder names from acknowledgements should be matched with the corresponding unique funder ID from the registry.

You can search funding metadata manually using our funding data search, or programmatically via our REST API. This data not only clarifies the scholarly record, but makes life easier for researchers who may need to comply with requirements to make their published results publicly available.

Watch the introductory Open Funder Registry animation in your language:

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Benefits of the Open Funder Registry

There are many benefits of clear, transparent, and measurable information on who funded research, and where it has been published. The OFR facilitates accurate funding metadata, which in turn enables multiple parties to better understand the research funding landscape:

Readers and researchers can read and assess literature in the context of knowing who funded it;
Research institutions can monitor the published outputs of their researchers;
Publishers can track who is funding their authors, and check if they’re meeting funding mandates;
Service providers can offer integrated time-saving features to their users; and
Funders can easily track the reach and return of the work they have supported.

How the Open Funder Registry works

Authors acknowledge the funding sources for their research in their publications. Using the registry, members can find the unique IDs for these funders, standardize this metadata and send it to us.

The registry is donated by Elsevier, and is updated around every 4-6 weeks with new and updated funder records. Existing entries are also reviewed to make sure that they are accurate and up-to-date. We can then make it openly available through our funding data search and our API. If you spot anything that doesn’t look right, please let us know. You can also download a .csv file of the latest registry. Using the OFR, members can find the unique IDs for these funders, standardize this metadata to send it to us.

Obligations and fees for the Open Funder Registry

The OFR is open to everyone. There are no fees for members depositing funding data. Open Funder Registry search and our API are also freely available.

Members must include the OFR ID for each funder if it is present in the Registry. If a funder is not in the Registry and does not have an ID, include the name of the funder.

How to participate in the Open Funder Registry

To access the OFR, you do not need to be a member, but you need to be a member to include OFR IDs in your Crossref metadata. Anyone who’s interested can simply enter an organisation’s name into the Open Funder Registry search to view content connected to funding sources. The metadata in the registry is also openly available via our API, and as a downloadable RDF file. Learn more about accessing the OFR.

Depositing metadata (members): collect funder names and grant numbers from your authors through your manuscript tracking system (or extract them from acknowledgements sections) and match them with the corresponding Funder IDs from the registry. Once this is done, it’s easy to add these three additional pieces of metadata - funder name, funder id, and grant number - as additional metadata in the regular Crossref content registration service. Learn more about how to collect and register funding data.

Whenever you register content with us, make sure you include funder names and grant numbers in the submission:

If you are using a content registration helper tool - the Crossref XML plugin for OJS, the web deposit form, or the new Metadata Manager tool - simply enter funder names and grant numbers in the relevant fields. For OJS, you must be running at least OJS 3.1.2 and have the Crossref funding plugin enabled.
If you’re depositing XML with Crossref, include your funding data in your XML.

Retrieving metadata: you can view the content that has cited a particular funding source by entering the organisation’s name into the Open Funder Registry search. If you prefer a machine-readable query, use our REST API. If you have questions about how your organisation appears in the registry then please get in touch. Learn more about the OFR and our other services on our funder community page.

Download the Open Funder Registry factsheet, and explore factsheets for other Crossref services and in different languages.

Getting started with Open Funder Registry (OFR)

Learn more about the Open Funder Registry (OFR) in our documentation.

Similarity Check

Kathleen Luschek — Wed, 08 Apr 2020 00:00:00 +0000

A service provided by Crossref and powered by iThenticate—Similarity Check provides editors with a user-friendly tool to help detect plagiarism.

Our Similarity Check service helps Crossref members prevent scholarly and professional plagiarism by providing immediate feedback regarding a manuscript’s similarity to other published academic and general web content, through reduced-rate access to the iThenticate text comparison software from Turnitin.

Only Similarity Check members benefit from this tailored iThenticate experience that includes read-only access to the full text of articles in the Similarity Check database for comparison purposes, discounted checking fees, and unlimited user accounts per organisation.

Watch the introductory Similarity Check animation in your language:

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With editors under increased pressure to assess higher volumes of manuscript submissions each year, it’s important to find a fast, cost-effective solution that can be embedded into your publishing workflows. Similarity Check allows editors to upload a paper, and instantly produces a report highlighting potential matches and indicating if and how the paper overlaps with other work. This report enables editors to assess the originality of the work before they publish it, providing confidence for publishers and authors, and evidence of trust for readers. And as the iThenticate database contains over 78 million full-text scholarly content items, editors can be confident that Similarity Check will provide a comprehensive and reliable addition to their workflow.

Making sure only original research is published provides:

peace of mind for publishers and authors that their content is identified and protected,
a way for editors to educate their authors and ensure the reputation of their publication, and
clarity for readers around who produced the work.

Benefits of Similarity Check

Similarity Check participants enjoy use of iThenticate at reduced cost because they contribute their own published content into Turnitin’s database of full-text literature. This means that as the number of participants grows, so too does the size of the database powering the service. More content in the database means greater peace of mind for editors looking to determine a manuscript’s originality.

If you participate in Similarity Check, not only do you get reduced rate access to iThenticate, but you also have the peace of mind of knowing that any similarity between your published content and manuscripts checked by other publishers will be flagged as a potential issue too.

As a Similarity Check user, you also see extra features in iThenticate, such as enhanced text-matches within the Document Viewer.

How the Similarity Check service works

To participate in Similarity Check, you need to be a member. Similarity Check subscribers allow Turnitin to index their full catalogue of current and archival published content into the iThenticate database. This means that the service is only available to members who are actively publishing DOI-assigned content and including in their metadata full-text URLs specifically for Similarity Check.

Turnitin indexes members’ content directly via its Content Intake System (CIS). Its CIS accesses our metadata daily to collect the full-text content links provided by our members within their metadata. Turnitin follows these URLs and indexes the content found at each location.

When you apply for the Similarity Check service, Turnitin will check that they can access your existing content via the full-text URLs in your Crossref metadata. Once confirmed, you’ll be provided with access to the iThenticate tool where you will be able to submit manuscripts to compare against the corpus of published academic and general web content in Turnitin’s database. You can do this in the iThenticate tool, or through your manuscript submission system using an API. iThenticate provides a Similarity Report containing a Similarity Score and a highlighted set of matches to similar text. Editors can then further review matches in order to make their own decision regarding a manuscript’s originality.

Fees for Similarity Check

Similarity Check fees are in two parts: an annual service fee, and a per-document checking fee.

The annual service fee is 20% of your Crossref annual membership fee and is included in the renewal invoices you receive each January. When you first join Similarity Check, you’ll receive a prorated invoice for the remainder of that calendar year.

Per-document checking fees are also paid annually in January. Volume discounts apply, and your first 100 documents are free of charge.

Similarity Service status page

Check the Turnitin service status page for real-time updates on system performance and any ongoing issues that may impact your Similarity Check service.

Getting started with Similarity Check

Learn more about Similarity Check in our documentation.

Update 2024: We are no longer able to offer the Similarity Check service to members based in Russia. Find out more.

Event Data terms of use

Martyn Rittman — Fri, 10 Nov 2017 00:00:00 +0000

Version 1.0

Who are we?

Crossref is a not-for-profit membership organisation providing certain technology services to the scholarly community on a noncommercial basis.

What is Crossref Event Data?

Crossref Event Data [the “Service”] is a Crossref service which provides a unique record of the relationship between web activity and specific scholarly content items (e.g. a journal article which has been referenced on a Wikipedia page). The Service is a hub for the collection, storage and distribution of data concerning these relationships. When a relationship is observed between a Crossref-registered content item and a specific web activity, the data is expressed in the Service as an “Event”. An “Event” is the record of a relationship between an item of registered content and a specific activity. The Service provides Events from a variety of web sources. Each web source is referred to as a “Data Contributor”. A “Data Contributor” means the location where a relationship was observed. The Events, and all original data from the Data Contributor, are available in the Service via an API.

What are the Terms of Use for Crossref Event Data?

To facilitate data access and maximal reuse, all Events provided in the Service are tagged with a license that is conformant with the principles laid out in the Open Definition. This ensures that data made available in the Service can be made publicly available and reused, in accordance with the conditions of the specific license associated with each Event. To this end, the service will only include data from Data Contributors who can provide this to the service via a license conformant with the Open Definition.

Consumers of the Service must ensure they abide by the conditions set out in the license tagged to each Event. In addition, consumers must also ensure to comply with any conditions set out in both the Data Contributor’s Privacy Policy as well as the Crossref Privacy Policy.

The Crossref Event Data service will respect the restrictions provided in robots.txt to ensure the service does not follows links when directed not to by these files. In addition, like search engines, Crossref runs software which visits websites. Events from our Newsfeeds, Reddit Links and Web sources are derived in this way.

Data from all Data Contributors is made available in the Service via the Creative Commons CC-0 1.0 license waiver, with the exception of the following Data Contributors listed below:

Data Contributor	Terms of Use / License
Crossref Metadata	Made available without restriction
Cambia Lens	Creative Commons CC-BY-SA 4.0
Stack Exchange Network	Creative Commons CC-BY 4.0

Privacy

In addition to the license associated with each Event, consumers of the Service must also ensure to comply with any conditions set out in the both the Crossref Privacy Policy as well as the Data Contributor’s own Privacy Policy. It’s a Service requirement that you adhere to the conditions stated in these policies. Every Event we provide via an API will contain the link to the Crossref Terms of Use page, where all the information and links you need regarding use and reuse will be available.

Where there are specific privacy policies of which Crossref is aware, that are associated with a particular Data Contributor, they are listed below.

Data Contributor	Privacy Policy
Cambia Lens	Cambia Lens Privacy Policy
Crossref Metadata	Crossref Privacy Policy
DataCite Metadata	DataCite Privacy Policy
Hypothes.is	Hypothesis Privacy Policy
Reddit	Reddit Privacy Policy
Stack Exchange Network	Stack Exchange Privacy Policy
Twitter	Twitter TOS
Wikipedia	Wikimedia Foundation Privacy Policy
Wordpress.com	Automattic Privacy Policy

Need to contact us?

Please email us at eventdata@crossref.org with any questions or feedback.