Aurner, Robert Ray
Manual for effective business correspondence / Robert Ray Aurner
South-Western Publishing Company, 1939
Buku Teks
King, F.W
English business letters : commercial correspondence for foreign students/F.W. King, D. Ann Cree.
Longmans , 1979
Buku Teks
Bouwens, C.
English Commercial correspondence
Persatuan Tenaga, 1957
Buku Teks
Murphy, Herta A.
Effective business communications
McGraw-Hill, 1991
Buku Teks
Webster's guide to business correspondence
Merriam-Webster, Inc., 1988
Buku Teks