Gaya APA

Azar, B, S., Hagen, S, A. (2009). Understanding And Using English Grammer, Fourth Edition With Answer Key (Ed. 1). United States of America: United States of America.

Gaya MLA

Azar, Betty, S., Hagen, Stacy, A. "Understanding And Using English Grammer, Fourth Edition With Answer Key". Ed. 1 United States of America: United States of America, 2009. Text.