Content Provider
LeibnizOpen (The Leibniz Association)
20
Arctic Data Center (via DataONE)
3
DataCite Metadata Store (German National Library of Science and Technology)
2
Unknown
2
Directory of Open Access Journals: DOAJ Articles
1
MDPI Open Access Publishing
1
Renate - Repositorium für Naturwissenschaften und Technik (TIB Hannover)
1