Content Provider
Copernicus Publications: E-Journals
20
Unknown
7
MDPI Open Access Publishing
5
DataCite Metadata Store (German National Library of Science and Technology)
3
BORIS (Bern Open Repository and Information System, University of Bern)
1
HighWire Press (Stanford University)
1
IRD (Institute de recherche pour le développement): Horizon
1
PubMed Central (PMC)
1