PPT Slide
Mardia KV, Kent JT, Bibby JM: Multivariate analysis. London, Academic 1994. ISBN 0124712525 (Pbk), 0124712509
Reyment R, Jöreskog KG: Applied factor analysis in the natural sciences. Cambridge Univ Press 1996. ISBN 0521575567 (Pbk), 0521412420