Initiative for Open Citations

The citations are stored in Crossref and are made available through the Crossref REST API. They are also available from the OpenCitations Corpus, a database that harvests citation data from Crossref and other sources. The data are considered by those involved in the Initiative to be in the public domain, and so a CC0 licence is used. and IOP Publishing participates to implement their commitment to the San Francisco Declaration on Research Assessment. == Launch ==

The initiative was established in response to a paper on citations in Wikidata, Citations needed for the sum of all human knowledge: Wikidata as the missing link between scholarly publishing and linked open data, given by Dario Taraborelli, head of research at the Wikimedia Foundation, at the eighth Conference on Open Access Scholarly Publishing, in September 2016. • OpenCitations • Wikimedia Foundation • PLOS • eLife • DataCite • The Centre for Culture and Technology at Curtin University At the time of launch, 64 organisations, including the Wellcome Trust, the Bill And Melinda Gates Foundation and the Alfred P. Sloan Foundation, 29 of these organisations were publishers who had agreed to share their citation metadata openly. On 8 August 2017, the Initiative released on open letter to stakeholders. The same month, the British Library became a member organisation. == Growth ==

Elsevier, who contribute 30% of the citation metadata in Crossref, Elsevier claimed in response that they could not release their data for free due to loss of licensing revenue from their proprietary Scopus citation services. Elsevier finally joined the initiative in January 2021 after the data was already available with an Open Data Commons license in Microsoft Academic. In August 2022, the number of articles whose reference lists were free to access and reuse exceeded 60 million, out of 134 million articles indexed by Crossref. == See also ==