Berstein, D. A., & Roy, E. J. (1994). Psychology (3rd.ed.). Houghton Mifflin.

Berstein, Douglas A., and Edward J. Roy. Psychology. 3rd.ed. Geneva: Houghton Mifflin, 1994.

Berstein, Douglas A., and Edward J. Roy. Psychology. 3rd.ed. Houghton Mifflin, 1994.