Knight - Orbit 2 (1965, 1972), Orbit Science Fiction #1 (1965, 1966), Worlds to Come (1966), Box: 11, Folder: 21. 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/230305 Accessed May 19, 2024.