Program Project, Communication Research with Retarded Children, Joseph Spradlin, 4354-11, HD-00870-11, June 27, 1973, Box: 60, Folder: 4. 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/455374 Accessed June 02, 2024.