Hinrichs, Roger A., author
Thomson, Brooks/Cole, 2006
Buku Teks
Borsboom, Denny, author
Cambridge university press , 2005
Buku Teks
Krol, Ed, author
O`Reilly and Associates, 1992
Buku Teks
edited by Alistair Tough, Michael Moss
Chandos Publishing, 2006
Buku Teks
McEwen, F. L.
John Wiley & Sons, 1979
Buku Teks