The site uses institutional collections for historical context and marketplace pages for current category structure—not as automatic authentication.
Institutional and preservation sources
- National Park Service, Preservation Brief 25: The Preservation of Historic Signs
- National Park Service, Route 66: How to Preserve Your Sign
- Smithsonian National Museum of American History, Warshaw Collection advertising materials
- Smithsonian, Pepsi-Cola Advertising Collection
- Library of Congress, American Sign Museum photographic record
- American Sign Museum
Marketplace structure
How sources are used
Museum objects and archives help establish historical use, brand campaigns, materials, and visual culture. Preservation sources frame conservative care. Marketplace listings reveal current vocabulary and supply, but seller statements are not treated as independent proof of authenticity.