The Progressive Salesman; The Direct Salesman's Own Newspaper. Cincinnati, Ohio: The Progressive Salesman, April 1935

The Progressive Salesman; The Direct Salesman's Own Newspaper. Cincinnati, Ohio: The Progressive Salesman, April 1935, Volume: Gilbert Q159. Robert L. Gilbert First Issues collection, Gilbert. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/527159 Accessed December 27, 2025.