Content Provider
Maine State Documents (Maine State Library)
19
Western Kentucky University (WKU): TopScholar
8
DataCite Metadata Store (German National Library of Science and Technology)
6
Hathi Trust Digital Library
2
University of Michigan: Digital Collections
2
Unknown
2
York University Digital Library
2
Bavarian Digital Repository (BDR - Bayerische Staatsbibliothek Munich, BSB)
1
University of Minnesota, Morris (UMM): Digital Well
1
University of Nebraska-Lincoln: DigitalCommons@UNL
1