"The New Marxism and Human Values", Human Values in a Secular World (ed. R. Apostol), New York: Humanities, pp. 57-80, 1970, Box: 13, Folder: 20. Personal papers of Richard T. De George, PP 531. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/315353 Accessed June 18, 2025.