Highway News. Washington, D.C.: National Association of Motor Bus Operators, April 1939

Highway News. Washington, D.C.: National Association of Motor Bus Operators, April 1939, Volume: Gilbert Q102. Robert L. Gilbert First Issues collection, Gilbert. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/526179 Accessed December 27, 2025.