Gaya APA

Azar, B, S., Hagen, S, A. (2009). Understanding and Using English Grammar (4). : Paerson Longman.

Gaya MLA

Azar, Betty, S.., Hagen, Stacy, A.. "Understanding and Using English Grammar". 4 : Paerson Longman, 2009. Mata Kuliah Umum.