Content Provider
DataCite Metadata Store (German National Library of Science and Technology)
48
German Aerospace Center: elib - DLR electronic library
8
KITopen (Karlsruhe Institute of Technologie)
4
Springer Nature (via Crossref)
3
DigiZeitschriften: The German digital journal archive (Göttingen University Library)
2
WikiBooks - Open-content textbooks
2
Wiley Online Library
2
Directory of Open Access Journals: DOAJ Articles
1
GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam)
1
Gutenberg Open Science (Open-Science-Repository of the Johannes Gutenberg-University Mainz)
1
TU Darmstadt: tuprints
1
University of Innsbruck: Digital Library (Universitäts- und Landesbibliothek Tirol)
1
Unknown
1
bonndoc - The Repository of the University of Bonn
1