Gaya APA

Postail, S. (1997). Travel by air: English For Special Purpose ( ESP) Coversational Approch (Cet. 3). Jakarta: Visipro.

Gaya MLA

Postail, Sara-Jane. "Travel by air: English For Special Purpose ( ESP) Coversational Approch". Cet. 3 Jakarta: Visipro, 1997. Text.