Ghiselli, Edwin E.
McGraw-Hill, 1955
Buku Teks
edited by Edwin A. Fleishman
Dorsey Press, 1967
Buku Teks
Lefton, Lester A.
Allyn and bacon , 1997
Buku Teks SO
Wortman, Camille B.
McGraw-Hill, 1992
Buku Teks SO
Myers, David G.
Worth, 1986
Buku Teks SO