Baron, Robert A.
Pearson, 2009
Buku Teks
Franzoi, Stephen L.
McGraw-Hill, Higher Education, 2009
Buku Teks
Myers, David G.
McGrow-Hill , 1987
Buku Teks
Sargent, S. W. Stansfeld
The Ronald Press, 1966
Buku Teks
Sherif, Muzafer
Harper Row, 1969
Buku Teks