8Harris,J.R.(1995).Where is the Child's Environment? A Group Socialization Theory of Development. Psychological Review, 102,458-489.
9Strough,J,Berg,C.A.&Meegan,S.P.(2001 ).Friendship and Gender Differences in Task and Social Interpretations of Peer Collaborative Problem Solving.Social Development, 10,1-22.
10Fabes,R.A Martin, C.L., & Hanish,L.D.(2003). Young Children's Play Qualitites in Same-,Other-, and Mixed-Sex Peer Groups. Child Development.74, 921-932.