Content Provider
Biodiversity Heritage Library (BHL)
104
Bavarian Digital Repository (BDR - Bayerische Staatsbibliothek Munich, BSB)
19
Harvard University: Harvard Collections
2
DataCite Metadata Store (German National Library of Science and Technology)
1
Memorial University of Newfoundland: Digital Archives Initiative (DAI)
1
OPARU (OPen Access Repository of Ulm University)
1
Project Gutenberg (PG)
1
UNESDOC - UNESCO Digital Library
1
University of Michigan: Digital Collections
1