"Synthese index to volumes 1-17 (1936-1967)", D. Reidel Publishing Company, Dordrecht-Holland

"Synthese index to volumes 1-17 (1936-1967)", D. Reidel Publishing Company, Dordrecht-Holland, Box: 6, Folder: 51. 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/315176 Accessed December 24, 2025.