McCorkle, Chester O., author
Jossey-Bass Publishers, 1982
Buku Teks
Lewis, John W., author
Cornell University Press, 1963
Buku Teks
S. Husin Ali, author
Oxford University Press, 1975
Buku Teks
Harper and Brothers, 1959
Buku Teks
Sherif, Muzafer, author
John Wiley & Sons, 1962
Buku Teks