Dixon, Lois, Conditional Stimulus Control over Choice Responding, HD-11194, Correspondence, 1978 - 1981, Box: 25, Folder: 22. University of Kansas Schiefelbusch Institute for Life Span Studies records, RG 35. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/452931 Accessed May 16, 2025.