Harman, Harry H.
Modern factor analysis
The University of Chicago Press, 1976
 Buku Teks
Whittaker, E.T.
A course of modern analysis : an introduction to the general theory of infinite processes and of analytic functions; with an account of the principal trancendental functions / E.T. Whittaker, G.N. Watson
Cambridge University Press, 1965
 Buku Teks
Edwards, Allen L.
Statistical analysis
Rinehart and Winston , 1958
 Buku Teks
Studies in item analysis and prediction / editor Herbert Solomon
Stanford Univ. Press ., 1961
 Buku Teks
Lewis, Edward E.
Methods of statistical analysis in economics and business / by Edward E. Lewis
Houghton Mifflin , 1963
 Buku Teks