Content Provider
LeibnizOpen (The Leibniz Association)
45
Unknown
6
DataCite Metadata Store (German National Library of Science and Technology)
4
Apollo - University of Cambridge Repository
2
Renate - Repositorium für Naturwissenschaften und Technik (TIB Hannover)
2
Directory of Open Access Journals: DOAJ Articles
1
University of Bristol: Bristol Research
1