Typescript (1944) describing Hays invention related to process for forming oil shales (a continuation in part of Hays' co-pending application filed February 21, 1944), Box: 6, Folder: 19. Russell Randolph Hays papers, RH MS 564. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/278187 Accessed September 20, 2024.