5[4]Sherif, M. ,O.J.Harvey, B.J.White,W. R. Hood. Intergroup conflict and cooperation: the Robbers Cave experiment. Norman: University of Ofiahoma Book Exchange, 1961.
6[5]Sherif, M. Group conflict and cooperation: Their social psychology. London: Routledge & kegan Paul, 1966.
7[6]Tajfel, H. Experiments in intergroup discrimination. Scientific American,1970, vol. 223(5).
8[7]Tajfel,H. ,C.Flament,M. G. Billig,& R. F. Bundy. Social categorization and intergroup behavior. European journal of social psychology, 1971,(1).
9[8]Tajfel,H. ,& Turner,J.C.An integrative theory of intergroup conflict. In W.G.Austin and S.Worchel (Eds),The social psychology of intergroup relations. Monterey, Cal.: Brooks/Cole, 1979.
10[9]Billig, M. G. ,& H. Tajfel. Social categorization and similarity in intergroup behaviour. European journal of social psychology,1973,3.