Back, Kurt W.
John Wiley & Sons, 1977
Buku Teks
DeLamater, John D.
Colorado Westview Press, 2014
Buku Teks
Pines, Ayala
McGraw-Hill, 1993
Buku Teks
Baron, Robert A.
Heights Allyn and Bacon , 1991
Buku Teks
Holander, Edwin P.
Oxford University Press , 1981
Buku Teks