Gaya APA
Leo..[et.al], S., Sudiyarto, O, H. (2007).
English for Academic Purpose : Essay Writing .
Yogyakarta:
Andi.
Gaya MLA
Leo..[et.al], Sutanto., Sudiyarto, Oktaviani, Hastu.
"English for Academic Purpose : Essay Writing".
Yogyakarta:
Andi,
2007.
Book.