References/Notes/Attributions:
Source
A. J. Weekes (1986) A Genstat Primer. Edward Arnold.
M. Davenport and G. Studdert-Kennedy (1972) The statistical analysis of aesthetic judgement: an exploration. Applied Statistics 21, 324–333.
I. T. Jolliffe (1986) Principal Component Analysis. Springer.
References
Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.