Giallombardo, Rose
John Wiley & Sons, 1982
Buku Teks
Kaplan, Howard B.
Sage Publications, 1984
Buku Teks
Terrance M. Brungardt
Houghton Miffiln, 1983
Buku Teks
Trojanowicz, Robert C., 1941-
Prentice-Hall, 1987
Buku Teks
Arnold, William R.
Houghton Mifflin, 1983
Buku Teks