We are excited to share that COCI, the OpenCitations Index of Crossref open DOI-to-DOI citations, was on 12 May 2020 extended with more than 47 million additional citations , and has reached a total number of more than 702 million DOI-to-DOI citation links between more than 58 million bibliographic entities . The citations added in this the fifth release of COCI came from the most recent Crossref