Bakeman, R.,& Brownlee, J. R.(1980). The strategic use of parallel play: A sequential analysis. Child Development, 51, 873-878.
Brown, W. H., Odom, S. L.,& Holcombe, A.(1996). Observational assessment of young children’s social behavior with peers. Early Childhood Research Quarterly, 11, 19-40.
Davies, M. M.(1996). Outdoors: An important context for young children’s development. Early Child Development and Care, 115, 37-49.
Eiferman, R.(1970). Level of children’s play as expressed in group size. British Journal of Educational Psychology, 40, 161-170.
Epstein, J. L.(1989). The selection of friends. In T. J. Berndt & G. W. Ladd (Eds.), Peer relationships in child development. New York: Wiley. pp. 158-187.