Gaya APA
Grolier Business Library : Business Letter. (1999).
Hongkong:
Grolier International, Inc.
Gaya Chicago
Grolier Business Library : Business Letter.
.
Hongkong:
Grolier International, Inc,
1999.
.
Gaya MLA
Grolier Business Library : Business Letter.
.
Hongkong:
Grolier International, Inc,
1999.
.
Gaya Turabian
Grolier Business Library : Business Letter.
Hongkong:
Grolier International, Inc,
1999.
.