Butler, J.K., Jr. (1983). A vector model for describing and comparing profiles . Educational and Psychological Measurement, 43, 747-758.
2.
Cattell, R.B. (1948). Concepts and methods in the measurement of group syntality. Psychological Review, 55, 48-63.
3.
Osgood, C.E., & Suci, G.J. (1952). A measure of relation determined both by mean differences and profile information. Psychological Bulletin,49, 251-262.
4.
Shaw, M.E. (1976). Group dynamics: The psychology of small group behavior. New York: McGraw-Hill .