1. Axelrod, R. (1984). The evolution of cooperation. New York: Basic Books.
2. Azrin, N. H., and Lindsley, O. R. (1956). The reinforcement of cooperation between children. Journal of Abnormal and Social Psychology, 52, 100–102.
3. Baron, A., and Galizio, M. (1983). Instructional control of human operant behavior. Psychological Record, 33, 495–520.
4. Burgess, R. L., and Nielsen, J. M. (1974). An experimental analysis of some structural determinants of equitable and inequitable exchange relations. American Sociological Review, 39, 427–443.
5. Buskist, W. F., Barry, A., Morgan, D., and Rossi, M. (1984). Competitive fixed interval performance in humans: Role of “orienting” instructions. Psychological Record, 34, 241–257.