Harrison - Apeman, Spaceman (1965), Worlds of Wonder (1968), The Year 2000 (1967), The Year Two Million (1972), Ahead of Time (1968), Box: 9, Folder: 28. Corporate Papers of the Robert Mills Literary Agency, MS 307. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/230245 Accessed May 16, 2024.