Gaya APA

Hariyanto, S. (2006). English Business Correspondence: a Practical Guide for Business and Secretarial... (Cet. 5.--). Yogyakarta: Kanisius.

Gaya MLA

Hariyanto, Sugeng. "English Business Correspondence: a Practical Guide for Business and Secretarial...". Cet. 5.-- Yogyakarta: Kanisius, 2006. Text.