1. Alatalo, R. V., and Moreno, J., 1987, Body size, interspecific interactions, and use of foraging sites by tits, Ecology 68: 1773–1777.
2. Alcock, J., 1993, Animal Behavior: An Evolutionary Approach, 5th ed., Sinauer Associates, Sunderland, Massachusetts.
3. Allee, W. C., 1942, Social dominance and subordination among vertebrates, Biol. Symp. 8: 139–162.
4. Allee, W. C., 1951, Cooperation among Animals, Henry Schuman, New York.
5. Allee, W. C., Collias, N. E., and Lutherman, C. Z., 1939, Modification of the social order in flocks of hens by the injection of testosterone propionate, Physiol Zool. 12: 412–440.