"The Scout; stability and weight considerations in the design of a high-speed, co-axial, midget helicopter" [bound typescript with drawings and black and white photographs]. Compiled June, 1942, Box: 6, Folder: 15. Russell Randolph Hays papers, RH MS 564. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/278183 Accessed September 20, 2024.