1. Asher, S., Parker, J., & Walker, D. (1996). Distinguishing friendship from acceptance: Implications for intervention and assessment. In W. M. Bukowski, A. F. Newcomb, & W. W. Hartup (Eds.), The company they keep: Friendship in childhood and adolescence (pp. 366–405). New York: Cambridge University Press.
2. Barnes, D., & Todd, F. (1977). Communication and learning in small groups. London: Routledge and Kegan-Paul.
3. Bierman, K. (1986). Process of change during social skills training with preadolescents and its relation to treatment outcome. Child Development, 57, 230–240.
4. Blumenfeld, P. C., Marx, R. W., Soloway, E., & Krajcik, J. (1996). Learning with peers: From small group cooperation to collaborative communities. Educational Researcher, 25, 37–40.
5. Cairns, R., & Cairns, B. (1994). Lifelines and risks: Pathways of youth in our time. New York: Cambridge University Press.