Hays/E. Burke Wilford/H. H. Munsey (Bell Aircraft Corporation) correspondence, 1957, regarding Hays patent on Drop Center Rotor System (also p. 2 of related 1947 letter), Box: 8, Folder: 9. Russell Randolph Hays papers, RH MS 564. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/278217 Accessed November 23, 2024.