Learning and transfer of oddity as a function of apparatus and trials per problem

Robles, R. H., Belleville, R. E., & Grunzke, M. Measurement of the higher intellectual functioning in the chimpanzee. Aerosp. Med., 1961, 32, 121–125.

Hârlow, H. F. The formation of learning sets. Psychol. Rev., 1949, 56, 51–65.

Levine, M., & Harlow, H. F. Learning sets with one- and twelve-trial oddity problems. Amer. J. Psychol., 1959, 72, 253–257.

Harlow, H. F. Studies in discrimination learning by monkeys: V. Initial performance by experimentally naive monkeys on stimulus object and pattern discrimination. J. gen. Psychol., 1945, 33, 3–10.