Gaya APA

Azar, B, S., Hagen, S, A. (2011). Fundamentals of English grammar : with answer key (4th Ed.). New York: Pearson.

Gaya MLA

Azar, Betty, Schrampfer., Hagen, Stacy, A.. "Fundamentals of English grammar : with answer key". 4th Ed. New York: Pearson, 2011. Text.