Content Provider
DataCite Metadata Store (German National Library of Science and Technology)
814
Washington State University: WSU Libraries Digital Collections
18
Unknown
11
Copernicus Publications: E-Journals
4
Utah State University: DigitalCommons@USU
4
MDPI Open Access Publishing
3
Digital Collections of Colorado (Colorado State University)
2
HighWire Press (Stanford University)
2
Mountain Scholar (Digital Collections of Colorado and Wyoming)
2
BioOne Online Journals
1
CyberLeninka (Scientific Electronic Library)
1
Defense Technical Information Center: DTIC Technical Reports database
1
Hathi Trust Digital Library
1
LSU Digital Commons (Louisiana State University)
1
PubMed Central (PMC)
1
University of the Pacific, McGeorge School of Law: Scholarly Commons
1
University of the Pacific: Scholarly Commons
1