Cohen, J.rc: A profile similarity coefficient invariant over variable reflection. Proceedings of the 76th Annual Convention. New York: APA, 1968.
2.
Holley, W. and Guilford, J. P.: A note on the G index of agreement. EDUCATIONAL AND PSYCHOLOGICAL MEASUREMENT, 1964, 24, 749-753.
3.
Sjöberg, L. and Holley, W. : A measure of similiarity between individuals when scoring directions of variables are arbitrary. Multivariate Behavorial Research, 1967, 2, 377-384.