Risley, Todd, Day Care for Infants from Walking to Preschool Age, October 1, 1973, Box: 68, Folder: 15. 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/455609 Accessed July 11, 2025.