The VARCLUS Procedure

Anderberg, M. R. (1973), Cluster Analysis for Applications, New York: Academic Press.

Harman, H. H. (1976), Modern Factor Analysis, 3rd Edition, Chicago: University of Chicago Press.

Harris, C. W. and Kaiser, H. F. (1964), “Oblique Factor Analytic Solutions by Orthogonal Transformation,” Psychometrika, 32, 363–379.