1. The decent of man and selection in relation to sex.;C Darwin,1871
2. Social norms and human cooperation.;E Fehr;Trends in Cognitive Sciences,2004
3. Adaptation and natural selection.;GC Williams,1966
4. Sexual selection, social competition, and speciation.;MJ West-Eberhard;Quarterly Review of Biology,1983
5. The extended phenotype: the long reach of the gene.;R Dawkins,1982