Dark for 28 days
in Richard D. Walk Papers, of University of Akron. Cummings Center for the History of Psychology; with Richard David Walk, 1920-1999, Series Four: Research Files, 1945-1997. Subseries One: Visual Cliff Research, 1958-1996, Box M4928, Folder 2: Visual cliff data - kittens, 1960-1968 , 4 page(s)