Gaya APA
Hariyanto, S. (2006).
English Business Correspondence : A Practicak Guide for Business and Secretarial Students and Professional Secretaries .
Yogyakarta:
Kanisius.
Gaya MLA
Hariyanto, Sugeng.
"English Business Correspondence : A Practicak Guide for Business and Secretarial Students and Professional Secretaries".
Yogyakarta:
Kanisius,
2006.
Book.