Wheeler, Bayard O.
Harper & Row. Publisher, 1968
Buku Teks
Buku Teks
Griffin, Ricky W., author
Prentice-Hall, 2002
Buku Teks
Pride, William M., author
Hougton-Mifflin, 1988
Buku Teks
Mann, Richard A., author
South Western Cengage Learning, 2011
Buku Teks