The Crossref Curriculum

XML query results and errors

Query results may be requested in three different formats: XSD_XML, UNIXREF, and UNIXSD.

UNIXSD is the recommended and most robust format, but XSD_XML is the default for many services for legacy reasons.

Possible errors returned by malformed or insufficient queries include:

  • an invalid XML query will return no result (<body/>)
  • either first page or author must be supplied
  • either ISSN or journal title must be supplied
  • unreasonable DOI found (an unreasonable DOI does not follow the expected DOI format (10.XXXX/yyy...) and/or exceeds 200 characters)
  • piped query must contain either 9 pipes (for journals) or 11 pipes (for books/conference proceedings)
  • either ISSN/ISBN or series/volume title must be supplied.

Last Updated: 2020 April 8 by Laura J. Wilkinson