Content Provider
Unknown
68
Copernicus Publications: E-Journals
19
PubMed Central (PMC)
17
HighWire Press (Stanford University)
12
MDPI Open Access Publishing
9
Defense Technical Information Center: DTIC Technical Reports database
4
IRD (Institute de recherche pour le développement): Horizon
4
DataCite Metadata Store (German National Library of Science and Technology)
3
University of Florida: Digital Library Center
1
University of Rhode Island: DigitalCommons@URI
1
University of Southampton: e-Prints Soton
1
Western Washington University: CEDAR (Contributing to Education through Digital Access to Research)
1