Arnold, K. D. (1995). Lives of promise: What becomes of high school valedictorians: A fourteen-year study of achievement and life choices. San Francisco, CA: Jossey-Bass.
Elkind, D. (1967). Egocentrism in adolescence. Child Development, 38(4), 1025–1034.
Strack, F., Martin, L., & Stepper, S. (1988). Inhibiting and facilitating conditions of the human smile: A nonobtrusive test of the facial feedback hypothesis. Journal of Personality and Social Psychology, 54, 768-777.