Crossref

A not-for-profit membership organization that collects scholarly metadata and shares it openly. Its records are what PaperCitation checks most references against.

Crossref is a not-for-profit membership organization founded in 2000. Its aim is to make research outputs easier to find, cite, link, assess and reuse. Members from around the world register their content with Crossref, and Crossref shares the descriptive data about it (the “metadata”) through free, open APIs.

What the records hold. For a journal article: the title, authors, journal, volume, issue, pages, date and DOI. For some works, notices such as retractions.

Why it matters here. PaperCitation looks a DOI up in Crossref first. For references without a DOI, it searches Crossref by title and authors. It also reads retraction notices that Crossref publishes, which include the Retraction Watch database. See retraction.

Limits. Crossref only has what its members register. Many books, theses, reports and older works are missing, and some records contain mistakes or are incomplete. A reference that isn’t found in Crossref can still be real, which is why PaperCitation also searches OpenAlex, DataCite, Open Library, Google Books and PubMed.

You can use Crossref’s own metadata search at search.crossref.org to look a work up yourself.