Glahe, Fred R.
San Diego Harcourt Brace Jovanovich, Inc.,
Buku Teks
Folks, J. Leroy, author
John Wiley & Sons, 1981
Buku Teks
Lamont, Douglas, author
Blackwell Publishers, 1996
Buku Referensi
Chang, David W., author
Thomson/Delmar Learning, 2006
Buku Teks
Nunnally, Jum C., author
McGraw-Hill, 1970
Buku Teks