"The Marxist Heritage", Patterns in Western Civilization, 2nd. ed, ed. by James Woelfel and Sarah Trulove, Needham Heights, Massachussetts: Simon and Schuster, pp. 478-493, 1999

"The Marxist Heritage", Patterns in Western Civilization, 2nd. ed, ed. by James Woelfel and Sarah Trulove, Needham Heights, Massachussetts: Simon and Schuster, pp. 478-493, 1999, Box: 14, Folder: 84. 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/315490 Accessed March 03, 2026.