Content Provider
Cambridge University Press
26
Directory of Open Access Journals: DOAJ Articles
16
DataCite Metadata Store (German National Library of Science and Technology)
10
ScienceDirect (Elsevier - via Crossref)
4
Geological Society of London: Figshare
3
DataCite
2
Nanjing Institute of Geology and Palaeontology: NIGPAS OpenIR (Chinese Academy of Sciences)
2
Rice University: Digital Scholarship Archive
2
University of California: eScholarship
2
Unknown
2
Boston University: OpenBU
1
Imperial College London: Spiral
1
ScienceDirect (Elsevier)
1