Latest blog posts
Patricia Feeney
2025 March 19

Version 5.4.0 metadata schema update now available

This year, metadata development is one of our key priorities and we’re making a start with the release of version 5.4.0 of our input schema with some long-awaited changes. This is the first in what will be a series of metadata schema updates.

What is in this update?

Publication typing for citations

This is fairly simple; we’ve added a ‘type’ attribute to the citations members supply. This means you can identify a journal article citation as a journal article, but more importantly, you can identify a dataset, software, blog post, or other citation that may not have an identifier assigned to it. This makes it easier for the many thousands of metadata users to connect these citations to identifiers. We know many publishers, particularly journal publishers, do collect this information already and will consider making this change to deposit citation types with their records.

...Find out more
Martyn Rittman
2025 March 12

2025 public data file now available

Every year we release metadata for the full corpus of records registered with us, which can be downloaded for free in a single compressed file. This is one way in which we fulfil our mission to make metadata freely and widely available. By including the metadata of over 165 million research outputs from over 20,000 members worldwide and making them available in a standard format, we streamline access to metadata about scholarly objects such as journal articles, books, conference papers, preprints, research grants, standards, datasets, reports, blogs, and more.

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Patricia Feeney
2025 March 05

Come ROR with us: Using ROR IDs in place of Funder IDs

Today, we’re delighted to let you know that Crossref members can now use ROR IDs to identify funders in any place where you currently use Funder IDs in your metadata. Funder IDs remain available, but this change allows publishers, service providers, and funders to streamline workflows and introduce efficiencies by using a single open identifier for both researcher affiliations and funding organizations.

As you probably know, the Research Organization Registry (ROR) is a global, community-led, carefully curated registry of open persistent identifiers for research organisations, including funding organisations. It’s a joint initiative led by the California Digital Library, Datacite and Crossref launched in 2019 that fulfills the long-standing need for an open organisation identifier.

...Find out more
Susan Collins
2025 February 27

The GEM program - Year Two 2024

We began our Global Equitable Membership (GEM) Program to provide greater membership equitability and accessibility to organizations in the world’s least economically advantaged countries. Eligibility for the program is based on a member’s country; our list of countries is predominantly based on the International Development Association (IDA). Eligible members pay no membership or content registration fees. The list undergoes periodic reviews, as countries may be added or removed over time as economic situations change.

...Find out more
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Documentation

UNIXSD query output format

XML output formatsUNIXREF query output format

UNIXSD query results include member metadata as deposited (as with the UNIXREF format) as well as some Crossref-generated information about the metadata record. UNIXSD is the most comprehensive metadata output format available for our metadata records.

UNIXSD format will return deposited references for other members. References will also be returned to members querying for their own deposited data.

UNIXSD metadata

UNIXSD results contain a sequence of Crossref produced meta-metadata including:

  • book-id: a Crossref internal identifier assigned to a non-journal title (book, conference proceeding, database, standard, dissertation, or report/working paper)
  • citation-id: a Crossref internal identifier assigned to a DOI record
  • citedby-count: number of Cited-by matches identified by Crossref
  • created: the date the record was created
  • deposit-timestamp: timestamp provided in most recent submission
  • journal-id: a Crossref internal identifier assigned to a journal title
  • last-update: the date the record was last updated
  • member-id: a Crossref internal identifier assigned to a member
  • owner-prefix: the prefix that ‘owns’ (has permissions to update) the DOI record
  • prefix-name: name associated with the prefix
  • prime: the DOI a record is aliased to (if the record is aliased)
  • publisher-name: member account name
  • relation: related item, includes ‘type’ attribute to identify the identifier, and ‘claim’ to identify type of relationship
  • series-id: a Crossref internal identifier assigned to a series title (applies to book and conference proceeding series)

This meta-metadata is contained in a <crm-item> element, for example:

<crm-item name="citedby-count" type="number">0</crm-item>
<crm-item name="owner-prefix" type="string">10.1353</crm-item>
<crm-item name="citation-id" type="number">25715607</crm-item>
<crm-item name="journal-id" type="number">48965</crm-item>
<crm-item name="book-id" type="number" />
<crm-item name="series-id" type="number" />
<crm-item name="last-update" type="date">2007-08-07 15:31:43.0</crm-item>

The full metadata record as deposited by members is available as well. The member as-deposited XML will begin with the <crossref> element.

UNIXSD schema

UNIXSD results are generated using crossref_query_output3.0.xsd (schema | documentation)

Example UNIXSD result 

<crossref_result xmlns="http://www.crossref.org/qrschema/3.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="3.0" xsi:schemaLocation="https://www.crossref.org/qrschema/3.0 https://data.crossref.org/schemas/crossref_query_output3.0.xsd">
 <query_result>
  <head>
   <doi_batch_id>none</doi_batch_id>
  </head>
  <body>
   <query status="resolved">
 	<doi type="journal_article">10.1353/aq.1998.0005</doi>
 	<crm-item name="publisher-name" type="string">Johns Hopkins University Press</crm-item>
 	<crm-item name="prefix-name" type="string">Muse - Johns Hopkins University Press</crm-item>
 	<crm-item name="member-id" type="number">147</crm-item>
 	<crm-item name="citation-id" type="number">25715607</crm-item>
 	<crm-item name="journal-id" type="number">48965</crm-item>
 	<crm-item name="deposit-timestamp" type="number">20070206205234</crm-item>
 	<crm-item name="owner-prefix" type="string">10.1353</crm-item>
 	<crm-item name="last-update" type="date">2007-02-13T20:56:13Z</crm-item>
 	<crm-item name="created" type="date">2007-02-07T02:04:57Z</crm-item>
 	<crm-item name="citedby-count" type="number">1</crm-item>
 	<doi_record>
  	<crossref xmlns="https://www.crossref.org/xschema/1.0" xsi:schemaLocation="https://www.crossref.org/xschema/1.0 https://doi.crossref.org/schemas/unixref1.0.xsd">
   	<journal>
    	<journal_metadata language="en">
     	<full_title>American Quarterly</full_title>
     	<abbrev_title>American Quarterly</abbrev_title>
     	<issn media_type="electronic">1080-6490</issn>
    	</journal_metadata>
    	<journal_issue>
     	<publication_date media_type="print">
      	<year>1998</year>
     	</publication_date>
     	<journal_volume>
      	<volume>50</volume>
     	</journal_volume>
     	<issue>1</issue>
    	</journal_issue>
    	<journal_article publication_type="full_text">
     	<titles>
      	<title>&quot;Disturbing the Peace: What Happens to American Studies If You Put African American Studies at the Center?&quot;: Presidential Address to the American Studies Association, October 29, 1997</title>
     	</titles>
     	<contributors>
      	<person_name sequence="first" contributor_role="author">
       	<given_name>Mary Helen.</given_name>
       	<surname>Washington</surname>
      	</person_name>
     	</contributors>
     	<publication_date media_type="print">
      	<year>1998</year>
     	</publication_date>
     	<pages>
      	<first_page>1</first_page>
      	<last_page>23</last_page>
     	</pages>
     	<doi_data>
      	<doi>10.1353/aq.1998.0005</doi>
       	<timestamp>20070206205234</timestamp>
       	<resource>
http://muse.jhu.edu/content/crossref/journals/american_quarterly/v050/50.1washington.html</resource>
     	</doi_data>
    	</journal_article>
   	</journal>
  	</crossref>
 	</doi_record>
   </query>
  </body>
 </query_result>
</crossref_result>
XML output formatsUNIXREF query output format

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