Brown, Leland
Englewood Cliffs, N.J., Prentice Hall
Buku Teks
Hamilton, Cheryl
Wods Worth Publishing, 1993
Buku Teks
Bovee, Courtland L., author
Pearson/Prentice Hall, 2007
Buku Teks
Boone, Louis E., author
Dryden Press, 1996
Buku Teks
Boone, Louis E., author
Dryden Press, 1990
Buku Teks