Carrell, Michael R., author
Irwin, 1984
Buku Teks
Werther, William B., author
McGraw-Hill, 1993
Buku Teks
Beach, Dale S., author
Macmillan, 1980
Buku Teks
Strauss, George, author
Prentice-Hall, 1980
Buku Teks
Crane, Donald P.
Kent publishing company, 1986
Buku Teks