COCI, the OpenCitations Index of Crossref open DOI-to-DOI citations

"COCI, the OpenCitations Index of Crossref open DOI-to-DOI citations, is an RDF dataset containing details of all the citations that are specified by the open references to DOI-identified works present in Crossref, as of the latest COCI update. COCI does not index Crossref references that are not open, nor Crossref open references to entities that lack DOIs. The citations available in COCI are treated as first-class data entities, with accompanying properties including the citations timespan, modelled according to the OpenCitations Data Model. For an in-depth description of COCI, see: Ivan Heibi, Silvio Peroni, David Shotton (2019). Software review: COCI, the OpenCitations Index of Crossref open DOI-to-DOI citations. Scientometrics, 121 (2): 1213-1228. https://doi.org/10.1007/s11192-019-03217-6 ... COCI was first created and released on 4 June 2018...."