Gaya APA
Azar, B, S., Hagen, S, A. (2009).
Understanding And Using English Grammar Fourth Edition .
London:
Pearson Longman.
Gaya MLA
Azar, Betty, S., Hagen, Stacy, A.
"Understanding And Using English Grammar Fourth Edition".
London:
Pearson Longman,
2009.
Text.