"The similarities of the notion of freedom between Sartre and Kolakowski, Markovic, and Kosik" by Anton Donoso, 1976, Box: 4, Folder: 24. 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/315122 Accessed June 14, 2025.