Correspondence, 1950, 1959, 1969-1970, 1972-1973, 1980, 1983, 1986, Box: 7, Folder: 7. Robert C. Caldwell family papers, RH MS 627. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/272787 Accessed May 18, 2024.