Last September, we announced we’d be deprecating co-access and encouraging its ~100 users to use our multiple resolution service. We announced that no new DOIs will be placed in co-access from 1st of July 2026 and that the ensuing 6 months should be spent cleaning up records already in co-access and moving them over to multiple resolution.Â
We’re here with a reminder: co-access is being deprecated…and with an update: To help with the transition to multiple resolution, we offer a tool that simplifies the process and documentation about how to set up multiple resolution.Â
We’ve recently reached an important milestone for the research nexus: the works in our metadata corpus are now connected with over 2 billion citation links! This is a great opportunity to share a dedicated dataset and discuss why these are important for science.
The Crossref Nominating Committee is inviting expressions of interest to join the Board of Directors of Crossref for the term starting in January 2027. 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 22, 2026
Today is Global Accessibility Awareness Day, and accessibility has been on our minds lately. We’ve recently completed an internal audit of all our user interfaces, and have added a new accessibility page to our website, where you can find the accessibility documentation that we put together as part of the audit.
Cited-by supports members who display citations, enabling the community to discover connections between research outputs.
Scholars use citations to critique and build on existing research, acknowledging the contributions of others. Members can include references in their metadata deposits which Crossref uses to create links between works that cite each other. The number of citations each work receives is visible to anyone through our public APIs. Through our Cited-by service, members who deposit reference metadata can retrieve everything they need to display citations on their website.
Members who use this service are helping readers to:
easily navigate to related research,
see how the work has been received by the wider community,
explore how ideas evolve over time by highlighting connections between works.
Watch the introductory Cited-by animation in your language:
Cited-by begins with references deposited as part of the metadata records for your content. Learn more about depositing references.
A member registers content for a work, the citing paper. This metadata deposit includes the reference list. Crossref automatically checks these references for matches to other registered content. If this is successful, a relationship between the two works is created. Crossref logs these relationships and updates the citation counts for each work. You can retrieve citation counts through our public APIs.
Members can use the Cited-by service to retrieve the full list of citing works, along with all the bibliographic details needed to display them on their website.
Note that citations from Crossref may differ from those provided by other services because we only look for links between Crossref-registered works and don’t share the same method to find matches.
Obligations and fees for Cited-by
Participation in Cited-by is optional, but encouraged.
There is no charge for Cited-by.
Depositing references is not a requirement, but strongly encouraged if you are using Cited-by.
Best practice for Cited-by
Because citations can happen at any time, Cited-by links must be kept up-to-date. Members should either check regularly for new citations or (if performing XML queries) set the alert attribute to true. This means the search will be saved in the system and you’ll get an alert when there is a new match.
Depositing your own references is strongly encouraged if you use Cited-by. If you don’t, the citations you retrieve will not include those from your own works. This is likely to lead to under-reporting of citations counts by at least 20% and you are missing the opportunity to point readers to other similar works on your platform.
Also in the metadata is the number of citations a work has received, under the tag "is-referenced-by-count".
To retrieve the full list of citations you need be a member using Cited-by. While anyone can use an API query to see the number of citations a work has received, members can retrieve a full list of citing DOIs and callback notifications informing them when one of their works has been cited. Details of the citing works can be displayed on your website alongside the article.
Page maintainer: Martyn Rittman Last updated: 2021-February-09