The Duo-Graphic Magazine. Chicago: Illinois Commercial Men's Association and the Illinois Traveling Men's Health Association, 1930

The Duo-Graphic Magazine. Chicago: Illinois Commercial Men's Association and the Illinois Traveling Men's Health Association, 1930, Volume: Gilbert D284. Robert L. Gilbert First Issues collection, Gilbert. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/525805 Accessed December 27, 2025.