Language Intervention with the Retarded edited by J.E. McLean, D.E. Yoder and Schiefelbusch, 1972, Box: 10, item: 4. Personal Papers of Richard Schiefelbusch, PP 458. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/266515 Accessed February 18, 2025.