Guffey, Mary Ellen
Essentials of business communication
Cengage Learning Asia, 2008
 Buku Teks SO
Guffey, Mary Ellen
Essentials of business communication
PWS Publishing, 1991
 Buku Teks SO
Guffey, Mary Ellen
Essentials of business communication
Cengage Learning, 2008
 Multimedia
Harvard business essentials : business communication
Boston : Harvard Business School Press, 2004,
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Ebert, Ronald J.
Business essentials
Prentice-Hall, 2003
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