Paper presented at meetings of the Society for Research in Child Development, Boston, 1981.
in Richard D. Walk Papers, of University of Akron. Cummings Center for the History of Psychology, Series Four: Research Files, 1945-1997. Subseries One: Visual Cliff Research, 1958-1996, Box M4927, Folder 8: Visual cliff data - ducks, 1971 , 26 page(s)