1. Studying individual development;Bergman,1991
2. Stability and change in patterns of extrinsic adjustment problems;Bergman,1991
3. The influence of older adolescent on younger adolescents;Blyth;Journal of Early Adolescence,1981
4. The adjustments of early adolescents to school transitions;Blyth;Journal of Early Adolescence,1983
5. The ecology of human development;Bronfenbrenner,1979