[Engine mechanic's license issued to Robert L. Simons, circa 1930s]

United States. Department of Commerce. Aeronautics Branch, [Engine mechanic's license issued to Robert L. Simons, circa 1930s], [1998-05-05-B_text_007]. Museum of Flight Digital Collections, accessed 18/02/2026, https://digitalcollections.museumofflight.org/nodes/view/4004