Greenwood, Charles, Modeling Developmental Retardation in Low-SES Children, November 2, 1992, Box: 37, Folder: 6. 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/453883 Accessed May 22, 2025.