"The Marxist Heritage", Patterns in Western Civilization, ed. James Woelfel and Sarah Trulove, Needham Heights, Massachussetts: Ginn Press, pp. 113-124, 1991

"The Marxist Heritage", Patterns in Western Civilization, ed. James Woelfel and Sarah Trulove, Needham Heights, Massachussetts: Ginn Press, pp. 113-124, 1991, Box: 14, Folder: 39. 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/315445 Accessed March 04, 2026.