6[1]Trivers, R. L. The evolution of reciprocal altruism [J]. Quarter Review of Biology, 1971(46): 35-37.
7[2]Wilson, E. O. The War between the words: biological versus social evolution and some related issues: Section 2. Genetic basis of behavior-especially of altruism [J]. American Psychologist, 1975(46): 458-468.
8[3]Bar-Tal, D. Altruistic motivation [J]. Humboldt Journal of Social Relation, 1986(13): 3-14.
9[4]Wilson, E. O. Sociology: The New Synthesis [M]. Cambridge, Mass: Harvard University Press, 1976.
10[5]Sober, E. What is evolutionary altruism? [J] Canada Journal of Philosophy, 1988(14): 75-99.
4Charitable giving to higher education stabilizes in 2003; gift from alumni rebound after one - year decline.[EB/OL].http: //www. rand.org/news /press.04 /03.11.htm1-.
