Content Provider
University of Washington, Seattle: Digital Collections
5,931
DataCite Metadata Store (German National Library of Science and Technology)
28
Cambridge University Press
7
Informa
2
Canadian Science Publishing
1
Hathi Trust Digital Library
1
Informa (via Crossref)
1
Iowa State University Library Digital Collections
1
SAGE Publications
1
University of Michigan: Digital Collections
1
University of Nebraska-Lincoln: DigitalCommons@UNL
1