1. Acsadi, G. Y. and Nemeskeri, J. (1970)History of Human Life Span and Mortality. Akademiai Kiado, Budapest, Hungary.
2. Alexander, R. D. (1987).The Biology of Moral Systems. Aldine de Gruyter, NY, USA.
3. Ammerman, A. J., Cavalli-Sforza, L. L. and Wagener, D. K. (1976). Towards the estimation of population growth in Old World prehistory. InDemographic Anthropology: Quantitative Approaches (E. B. W. Zubrow, ed.), pp. 27–61, University of New Mexico Press, Albuquerque, NM, USA.
4. Bell, G. (1984) Evolutionary and nonevolutionary theories of senescence.Am. Nat. 124, 600–3.
5. Brown, J. L. (1986)Helping and Communal Breeding in Birds. Princeton University Press, Princeton, NJ, USA.