Guffey, Mary Ellen, author
PWS Publishing, 1991
Buku Teks
Guffey, Mary Ellen, author
Cengage Learning, 2008
Multimedia
Guffey, Mary Ellen, author
PWS-Kent, 1988
Buku Teks
Guffey, Mary Ellen, author
Cengage Learning Asia, 2008
Buku Teks
Boston : Harvard Business School Press, 2004,
Buku Teks