http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
National inventory of documentary sources in the United States
pt. 1. Federal records -- pt. 2. Manuscript Division, Library of Congress -- pt. 3. State archives, libraries and historical societies -- pt. 4. Academic libraries and other repositories.
Pt. 1-2 print indexes compiled by Victoria Agee [and others]
Pt. 3-4 indexes issued in microfiche and housed in binders.