1. Responses of bright, normal, and retarded children to learning tasks;Carrier;Cooperative Research Program of the Office of Education, Project No. 578,1961
2. Studies in activity level: I. Simple and complex task performance in defectives;Foshee;Amer. J. ment. Defic.,1958
3. Chance orders of alternating stimuli in visual discrimination experiments;Gellermann;J. genet. Psychol.,1933
4. Delay of reward and learning in mentally retarded and normal children;Hetherington;Child Develpm.,1964
5. Studies in activity level: VII. Effects of amphetamine drug administration on the activity level of retarded children;McConnell;Amer. J. ment. Defic.,1964