The document provides an overview of Crossref's metadata services, including ways to look up and match metadata related to DOIs, authors, citations, and funding data. It outlines REST and XML APIs for accessing and retrieving metadata, as well as examples of queries for finding specific records. Users are informed about conditions for searching, types of available metadata, and additional support resources.

1. Get started:
Looking up
metadata

2. funders
data
clinical
trialsgrant
#s DOI
funders
data
authors
preprint
funders
grant
#s
versions
preprint
funders
data
clinical
trials
updates
grant
#s
versions
preprint
reviews
data
DOI
grant
#s
versions
updates
updatesdata
data
data
data
data
data
data
citations
data
data
DOI
DOI
DOI
DOI
What are you
looking for?authors

3. Citation metadata
including…
author names, ORCIDs, affiliations, article titles,
ISSN, ISBN, pages, issue #, volume #s, dates, DOI

4. more metadata
reference lists, funding data, ORCIDs,
license data, clinical trial numbers, errata,
retractions, updates and more through our
Crossmark service, JATS-formatted
abstracts, relationships between items…

5. What do you want to do?
• Look up metadata for a DOI
• Match a reference / metadata to a DOI
• Look up / retrieve metadata based on defined
criteria
• Get everything

6. Have a DOI?
Metadata Search (https://search.crossref.org)
REST API (https://api.crossref.org)
XML API
OpenURL

13. XML metadata records
XML API:
http://doi.crossref.org/search/doi?
pid=youremail@example.org&format=unixsd&doi=10.1162/1526516017
50079104
OpenURL:
https://www.crossref.org/openurl?
pid=youremail@example.org&format=unixsd&id=doi:
10.1162/152651601750079104&noredirect=true

15. Match reference to record / DOI
Formatted reference?
Metadata Search *
REST API *
Simple Text Query form
XML API
OpenURL
Metadata fragment
Metadata Search
REST API
XML API (need to mark up,
minimum metadata
requirements)
* need to evaluate

16. Needs evaluation:!
- not always exact !
- will return approximate results!
- will also return other stuff !
Good for: !
finding approximate results, working with
messy data, evaluating matches on your own!
Exact:!
- field-by-field match!
- match or no match at all!
Good for: !
auto-populating lists of references!

17. • Search by title fragment, author name
• Find works related to an ORCID
• Search by ISSN
• Search by grant / award number
• Include / exclude terms (using + and !)

19. Simple Text Query

20. 3. Retrieve results

21. REST API
• Search, filter, facet, and sample Crossref metadata
• No login, no fee
• Do whatever you want with the metadata:
• Search
• Report on funding, publishing, author activities
• Ingest scholarly metadata
• Locate full text for content mining

22. What can I ask?
• What types of publications is Crossref
collecting DOIs for?
http://api.crossref.org/works?facet=type-
name:*&rows=0

23. What can I ask?
• See how many works have funder information
http://api.crossref.org/works?filter=has-funder:true&rows=0

24. All records for a prefix:
http://api.crossref.org/prefixes/10.xxxx/works
All records with funder information:
http://api.crossref.org/prefixes/10.xxxx/works?filter=has-funder-doi:true&rows=0
All records for a prefix with funder information:
http://api.crossref.org/prefixes/10.xxxx/works?filter=has-funder-doi:true
All records with a given funder published in 2017:
http://api.crossref.org/works?filter=is-update:true,from-pub-date:2017-01-01,funder:
10.13039/100000001,funder:10.13039/100000050
All records with ORCIDs:
https://api.crossref.org/works?filter=has-orcid:true
All records containing a given term:
http://api.crossref.org/works?query=quokka
REST API (https://api.crossref.org)

26. XML API
• Match references to DOIs
• Free (registration required)
• Good for reference linking

27. XML API
<query key="CR3" enable-multiple-hits="false"
forward-match="true” secondary-query="author-title">
<journal_title>Antiquity</journal_title>
<author search-all-authors="true">Anderson</
author>
<volume>87</volume>
<issue>337</issue>
<first_page>879</first_page>
<year>2013</year>
</query>
more info: https://support.crossref.org/hc/en-us/sections/202815006

28. XML API
<query enable-multiple-hits="false" key="key1">
<article_title match="fuzzy">Concluding remarks</
article_title>
<author search-all-authors="true">Somiari</
author>
</query>
Author / title query

29. XML API
<query key="q1" enable-multiple-hits="true">
<unstructured_citation>Hungate, B. A., &amp;
Hampton, H. M. (2012). Ecosystem services: Valuing
ecosystems for climate. Nature Climate Change, 2(3),
151-152.</unstructured_citation>
</query>
Unstructured citation

30. Format Content Type CrossRef DataCite mEDRA
RDF XML application/rdf+xml Yes Yes Yes
RDF Turtle text/turtle Yes Yes Yes
Citeproc JSON application/vnd.citationstyles.csl+json Yes Yes Yes
Schema.org in JSON-LD application/vnd.schemaorg.ld+json No Yes No
Formatted text citation text/x-bibliography Yes Yes Yes
RIS application/x-research-info-systems Yes Yes No
BibTeX application/x-bibtex Yes Yes Yes
CrossRef Unixref XML application/vnd.crossref.unixref+xml Yes No No
DataCite XML application/vnd.datacite.datacite+xml No Yes No
ONIX for DOI application/vnd.medra.onixdoi+xml No No Yes
Content negotiation (http://citation.crosscite.org/cn)
Retrieve metadata
records from
Crossref, DataCite,
and mEDRA

31. I want everything
• Metadata Plus (OAI-PMH and REST API)
• OAI-PMH deposit harvester (for members)

32. Questions?
support@crossref.org
http://support.crossref.org