Reference distribution

All metadata that members register with us is made available through our various metadata search and API services. However, references have historically been treated differently than all other metadata.

In July 2017 the Crossref board voted unanimously to remove the ability for members to make case-by-case opt-out choices for metadata distribution, and the membership agreement was updated accordingly.

Crossref members can choose to set their references to ‘Open’, ‘Limited’, or ‘Closed’, per prefix. New members joining from 2018 default to ‘Open’. Members who joined in 2017 or longer ago, have been set to ‘Limited’ unless they’ve informed us otherwise.

Reference distribution options

Around a third of our members include reference lists when they deposit metadata to register their content, usually in order to participate in our Cited-by service.

Members depositing references should contact our support team if they would like to change their setting to one of the following options:

Reference setting Description
Closed Your references are only used for the Crossref Cited-by service and are not distributed via any of the public Crossref interfaces.
Limited In addition, organizations that sign an agreement for our Metadata ‘Plus’ service can access your references. (This is the default for older accounts)
Open Everyone can access your references through our open APIs. (This is the default for accounts joining from 2018)

Background & rationale

Over the last ten years we have developed five machine interfaces and three human interfaces for accessing Crossref metadata. The organizations using Crossref metadata include publishers as well as third parties such as libraries and search/discovery/analytics tools. For example—American Chemical Society, ORCID, Jisc, CHORUS, Kudos, Elsevier, Altmetric, CCC, NASA, National Science Foundation, EBSCO, Springer Nature, Ex-Libris—and many hundreds of other publishers, platforms, researchers, and libraries.

The interfaces each offered slightly different metadata and features which was an inconsistent offering, and was confusing for both members and users. One of the features that was inconsistent is the case-by-case metadata opt-out we had been running for just one of the services, known as Enhanced CMS, which was for obtaining metadata specifically via the OAI-PMH interface.

Crossref was founded to enable a shared reciprocal linking and metadata exchange, removing the need for bilateral agreements between publishers and other service providers.

The best way to opt out of certain metadata sharing, is to not put it into Crossref. But there are a number of benefits to distributing references through Crossref, chiefly among them increased usage of your content—members benefit from increased usage when Crossref DOIs, metadata and references are propagated throughout the numerous scholarly communications systems that drive discoverability.


1) How do I know if I or my service provider includes references with our metadata deposits?

Please check with your production department or service provider; they should know. You can also query using our REST API with the has-references filter, using this query:*&rows=0 (your browser will need a json viewer plugin).

2) How do I find out whether our references are currently open, limited, or closed?

An output from our REST API is in this table showing a list of members with some references Open. See the report of members with some references set Closed. If you are not on those reports then you likely have your references set to ‘limited’ right now.

3) What are other members doing?

All new members are set to default have references Open. Members who joined prior to January 2018 have the default of Limited and need to let us know if they want it changed to Open, or Closed.

Please contact our technical support specialists if you have any questions and click here to let us know if you’d like to change your setting. Please include your organization’s name and the relevant DOI prefix(es) (starting 10.nnnn).

Last Updated: 2017 October 25 by Ginny Hendricks