Content Provider
University of Michigan: Digital Collections
91
Hathi Trust Digital Library
59
norden (Nordic Council of Ministers): Publications (DiVA)
42
Bavarian Digital Repository (BDR - Bayerische Staatsbibliothek Munich, BSB)
19
APS Digital Library (American Philosophical Society)
12
DataCite Metadata Store (German National Library of Science and Technology)
12
University of San Diego: Digital@USanDiego
4
OLAC: Open Language Archives Community
3
York University Digital Library
3
Project Gutenberg (PG)
2
UQAM - Université du Québec à Montréal: archipel
2
DataCite
1
Harvard University: Harvard Collections
1
Hungarian Electronic Library (MEK)
1
Institute of Volcanology and Seismology, Petropavlovsk-Kamchatsky: IVS FEB RAS Repository
1
Pomeranian Digital Library (PBC)
1
Princeton Theological Seminary: Theological Commons
1