Crandall, J. E. (1980). Adler’s concept of social interest: Theory, measurement, and implications for adjustment.Journal of Personality & Social Psychology,39, 481–495.
Lepper, M. R. (1985). Microcomputers in education: Motivational and social issues.American Psychologist,4, 1–18.
SAS Institute. (1982).SAS user’s guide. Statistics 1982 edition. Cary, NC: Author.