Content Provider
Copernicus Publications: E-Journals
15
Defense Technical Information Center: DTIC Technical Reports database
6
PubMed Central (PMC)
6
Unknown
5
MDPI Open Access Publishing
4
DataCite Metadata Store (German National Library of Science and Technology)
3
norden (Nordic Council of Ministers): Publications (DiVA)
2
HighWire Press (Stanford University)
1
IRD (Institute de recherche pour le développement): Horizon
1
University of Cumbria: Insight
1
University of Zurich (UZH): ZORA (Zurich Open Repository and Archive
1