Gaya APA

Hagen, S, A., Azar, B, S. (2009). English Grammar: Understanding and using (Ed.4). New York: Pearson Longman.

Gaya MLA

Hagen, Stacy, A.., Azar, Betty, S.. "English Grammar: Understanding and using". Ed.4 New York: Pearson Longman, 2009. Text.