1. DeVore, I., and Hall, K. R. L., in Primate Behavior (edit. by DeVore, I.), 20–52 (Holt, Rinehart and Winston, New York, 1965).
2. Crook, J. H., and Gartlan, J. S., Nature, 210, 1200–1203 (1966).
3. Jolly, A., The Evolution of Primate Behavior (Macmillan Company, New York, 1972).
4. Crook, J. H., in Sexual Selection and the Descent of Man (edit. by Campbell, B.), 231–281 (Aldine, Chicago, 1972).
5. Eisenberg, J. F., Muckenhirn, N. A., and Rudran, R., Science, 176, 863–874 (1972).