Content Provider
Bavarian Digital Repository (BDR - Bayerische Staatsbibliothek Munich, BSB)
8
DataCite
1
DataCite Metadata Store (German National Library of Science and Technology)
4
Digital Collections of Colorado (Colorado State University)
1
Harvard University: Harvard Collections
4
Hathi Trust Digital Library
17
Mountain Scholar (Digital Collections of Colorado and Wyoming)
1
OLAC: Open Language Archives Community
8
Princeton Theological Seminary: Theological Commons
4
Project Gutenberg (PG)
1
The Library of Congress: American Memory
1
University of Michigan: Digital Collections
11
Yale University: EliScholar
10