Program Project, Communication Research with Retarded Children, Joseph Spradlin, HD-00870-10, Submitted, June 23, 1972, Box: 60, Folder: 2. 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/455372 Accessed July 17, 2025.