Cooley, W. W. and Lohnes, P. R. (1971), Multivariate Data Analysis, New York: John Wiley & Sons.

Gnanadesikan, R. (1977), Methods for Statistical Data Analysis of Multivariate Observations, New York: John Wiley & Sons.

Hotelling, H. (1933), “Analysis of a Complex of Statistical Variables into Principal Components,” Journal of Educational Psychology, 24, 417–441, 498–520.

Kshirsagar, A. M. (1972), Multivariate Analysis, New York: Marcel Dekker.

Mardia, K. V., Kent, J. T., and Bibby, J. M. (1979), Multivariate Analysis, London: Academic Press.

Morrison, D. F. (1976), Multivariate Statistical Methods, Second Edition, New York: McGraw-Hill.

Pearson, K. (1901), “On Lines and Planes of Closest Fit to Systems of Points in Space,” Philosophical Magazine, 6, 559–572.

Rao, C. R. (1964), “The Use and Interpretation of Principal Component Analysis in Applied Research,” Sankhya A, 26, 329–358.