1. Acquisition of operant differentiation and discrimination in institutionalized retarded children;Barrett;Am. J. Orthopsychiat.,1965
2. A behavior evaluation program for retarded children;Barrett,1965
3. Naturally acquired and remediated reversals of differentiation and discrimination in retarded children;Barrett,1967
4. Deficits in acquisition of operant discrimination and differentiation shown by institutionalized retarded children;Barrett;Am. J. ment. Defic.,1962
5. When exceptions obscure the rule;Berkson;Ment. Retard.,1966