OpenAlex

A free, open catalog of scholarly works, authors and institutions, which PaperCitation uses to find papers that other databases miss.

OpenAlex is a free, open catalog of the world’s scholarly works, with their authors, journals and institutions. It launched in January 2022 as a replacement for Microsoft Academic Graph, which was retired at the start of that year. It is run by OurResearch, a nonprofit also known for Unpaywall. The data is released under the CC0 licence.

What it covers. Journal articles, conference papers, books and book chapters, datasets, dissertations, preprints and more, gathered from sources such as Crossref, ORCID, PubMed and arXiv. Its help pages report hundreds of millions of works, with tens of thousands added each day.

Why PaperCitation uses it. Many papers have no Crossref record, such as conference papers that were only posted as preprints. OpenAlex often knows them, and it can also flag a retracted paper.

Limits. OpenAlex is built automatically, so it can hold duplicate or incomplete records, and some works appear more than once under different DOIs. That’s why PaperCitation compares the year, the authors and the venue before it calls a record a match, and shows a “Possible match” when it isn’t sure.