Content Provider
LeibnizOpen (The Leibniz Association)
19
Unknown
2
DataCite Metadata Store (German National Library of Science and Technology)
1
Open-Access-Publikationsserver der Humboldt-Universität: edoc-Server
1
Renate - Repositorium für Naturwissenschaften und Technik (TIB Hannover)
1
Springer Nature (via Crossref)
1
University of Potsdam: publish.UP
1