Content Provider
GettDigital (Gettysburg College Digital Collections)
2
University of Miami: Digital Collections
2
University of Washington, Seattle: Digital Collections
2
Biodiversity Heritage Library (BHL)
1
DataCite Metadata Store (German National Library of Science and Technology)
1
Digital Repository of Scientific Institutes (RCIN)
1
Doria (National Library of Finland)
1
Illinois State Library: Illinois Digital Archives
1
PennState: Digital Collections
1
The Portal to Texas History (University of North Texas)
1