Quible, Zone K.
Business Communication
Prentice Hall International,inc, 1996
 Buku Teks
Quible, Zone K.
Business Communication
Prentice Hall International,inc, 1996
 Koleksi Publik
Ewald, Helen Rothschild
Business communication
Prentice Hall International, 1997
 Buku Teks
Dumont, Raymond A.
Business communications
Little, Brown, 1985
 Buku Teks
Quible, Zone K.
Business Communication
Prentice Hall International,inc, 1996
 Buku Teks