Seglin, Jeffrey L.
The AMA handbook of business letters
[American Management Association, American Management Association], 2002
 eBooks
Seglin, Jeffrey L.
The AMA handbook of business letters
Amacom, 1996
 Buku Referensi
Seglin, Jeffrey L., 1956-
The AMA Handbook of Business Letters / Jeffrey L. Seglin, Edward Coleman
Amacom, 2012
 Buku Teks SO
Poe, Roy W.
The McGraw-Hill handbook of business letters
McGraw-Hill, 1994
 Buku Referensi
Poe, Roy W.
The McGraw-Hill handbook of business letters
McGraw-Hill, 1988
 Buku Teks SO