Hoffamn, K. Douglas
Horcourt Colledge Publisher, 2002
Buku Teks
Hoffman, K. Douglas
Harcourt College Publishers, 2002
Buku Teks
Still, Richard R.
Prentice-Hall, 1988
Buku Teks
McDaniel, Carl, author
South Western Cengage Learning, 2012
Buku Teks
Still, Richard R., author
Prentice-Hall, 1966
Buku Teks