Latest blog posts
Luis Montilla
2025 June 23

Sprinting to Progress: Behind the scenes of our first metadata sprint

If you take a peek at our blog, you’ll notice that metadata and community are the most frequently used categories. This is not a coincidence – ommunity is central to everything we do at Crossref. Our first-ever Metadata Sprint was a natural step in strengthening both. Cue fanfare!. And what better way of celebrating 25 years of Crossref?

We designed the Crossref Metadata Sprint as a relatively short event where people can form teams and tackle short problems. What kind of problems? While we expected many to involve coding, teams also explored documenting, translating, researching—anything that taps into our open, member-curated metadata. Our motivation behind this format was to create a space for networking, collaboration, and feedback, centered on co-creation using the scholarly metadata from our REST API, the Public Data File, and other sources.

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Luis Montilla
2025 June 17

Evolving the preprint evaluation world with Sciety

This post is based on an interview with Sciety team at eLife.

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Susan Collins
2025 June 05

Destacando nuestra comunidad en Colombia

English version

Dado que Crossref celebra su 25º aniversario este año, nos gustaría destacar algunas de las regiones activas y comprometidas en nuestra comunidad global.

Durante los primeros 25 años, la composición de los miembros de Crossref ha evolucionado significativamente. De un puñado de grandes editoriales fundadoras, ahora tenemos más de 22.000 miembros de 160 países. Casi dos tercios de ellos se identifican como universidades, bibliotecas, entidades gubernamentales, fundaciones, editoriales académicas, e institutos de investigación.

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Lucy Ofiesh
2025 May 14

Our annual open call for expressions of interest to join our board

The Crossref Nominating Committee invites expressions of interest to join the Board of Directors of Crossref for the term starting in January 2026. The committee will gather responses from those interested and create the slate of candidates that our membership will vote on in an election in September.

Expressions of interest will be due Monday, June 9th, 2025

...Find out more
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Documentation

Using the match attribute

Our query engine operates by evaluating several logic rules in order. Each rule focuses on certain fields in the query, with the first rule processing the entire query. If any rule returns a single DOI as its output, this DOI is taken as the result for the query, and rule processing terminates.

In an XML query you can exercise some control over how the query engine works by using the match attribute that is available on many query elements.

  • fuzzy: Fuzzy matching is allowed but the field is not optional, it must be matched.
  • optional: In most cases, optional is a default property. Using a value that excludes optional (for example, match="") tells the query engine that this field is not optional and must be present, and matched, for a DOI match to occur.
  • exact: Instructs the query engine to not apply any of its fuzzy comparison logic. This is the same as match="" (which means not optional and not fuzzy). Using exact is not compatible with optional, or fuzzy.
  • null: Instructs the query engine to match on the query element if it is not present in the metadata. When using this option it makes no sense to provide an element value (for example, the correct style would be <author match="null"/>

Multiple values may be assigned (as in match="optional fuzzy"). Typical uses include:

  • match="fuzzy" - instructs the query engine to apply its fuzzy comparison logic for this field
  • match="optional fuzzy" - a rule may drop the field altogether or use fuzzy matching
  • match="exact" - field must be matched and no fuzzy matching is allowed
  • match="" - same as match="exact"

Page owner: Martyn Rittman   |   Last updated 2020-April-08