Guest blog post by Alberto Martín-Martín, Facultad de Comunicación y Documentación, Universidad de Granada, Spain <albertomartin@ugr.es> In this post, as a contribution to Open Access Week, Alberto Martín-Martín shares his comparative analysis of COCI and other sources of open citation data with those from subscription services, and comments on their relative coverage. Comprehensive bibliographic metadata is essential for the

On September 27, OpenCitations’ director Silvio Peroni, together with Niels Stern (DOAB/OAPEN) and James MacGregor (PKP), held the online workshop “How Open Infrastructure Benefits Libraries” during the Open Access Tage 2021. Open-Access-Tage (Open Access Days) are the annual central platform for the steadily growing Open Access and Open Science community from Germany, Austria and Switzerland ,

With the numerous September events in which the OpenCitations’ directors have recently been involved behind us, it is now time to announce the participation of our director Silvio Peroni in two October events.

Yesterday I gave a lightning talk at the 2021 OASPA Conference, with the title OpenCitations – what does the future hold? The poster accompanying my talk, published on Zenodo at https://doi.org/10.5281/zenodo.5526713, is reproduced below. Here is what I said: = = = Most of the talks at this conference have focussed on open access to textual content.

No-one is quite sure of the total number of scholarly publications within the global corpus. Indeed that number will be strongly influenced by the degree to which, in addition to books and journal articles, one includes within the definition of scholarly publications ‘grey literature’ such as reports published by official bodies, patents, etc.

It’s been a month since the announcement of 1.09 Billion Citations available in the July 2021 release of COCI, the OpenCitations Index of Crossref open DOI-to-DOI citations.   We’re now proud to announce the September 2021 release of COCI, which is based on open references to works with DOIs within the Crossref dump dated August 2021.

In his call for open citations, Dario Taraborelli hailed the scholarly citation graph (in which the nodes (vertices) are individual academic publications and the links (edges) represent bibliographic citations from one publication to another) as one of humankind’s most important intellectual achievements.

“The competitive benefits of closing access to citation data diminish with each new citation released to the public domain, but the benefits of open data remain. Going forward, citation data is almost completely public domain” . With these words, from the article “A tipping point for open citations data“ (July 15, 2021), Ian Hutchins celebrated the threshold crossing of one billion citations on public-domain databases in February 2021.

We congratulate and thank Elsevier, the world’s largest academic publisher, for endorsing the DORA Declaration on Research Assessment (https://sfdora.org/), thereby joining the hundreds of other publishers and scientific organizations which have endorsed DORA over the previous eight years, and also for making a commitment to open the references from all its journal articles submitted to Crossref.

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