From a Centre for Science and Technology Studies, Leiden University, The Netherlands Blog Post:
The Initiative for Open Citations (I4OC) encourages scholarly publishers to make the references found in their journals and books openly available through Crossref. With a few exceptions (most notably the American Chemical Society, Elsevier, IEEE, and Wolters Kluwer Health), almost all large publishers support the initiative. So far, this support has resulted in approximately half of all references deposited in Crossref being openly available, yielding about half a billion open references.
[Clip]
Thanks to I4OC, Crossref has the potential to become an openly available source of citation data covering a large share of all scholarly literature.
Source: Centre for Science and Technology Studies, Leiden University, The Netherlands
[Clip]
A large share of the scholarly literature indexed in WoS and Scopus is also available in Crossref. For recent years, 68% of the WoS publications and 77% of the Scopus publications can be matched with Crossref using DOIs as a crosswalking mechanism. These figures are likely to underestimate the true overlap between the data sources, since matching based on DOIs presents several difficulties, such as missing, incorrect, and duplicate DOIs. To improve matching, publishers and data providers need to work together to offer more comprehensive and more accurate DOI data.
Direct to Complete Blog Post (approx. 2800 words + Five Charts/Tables)
See Also: Crossref ||| Crossref Metadata Search ||| Crossref Funder Search