Gaya APA

Betty, S., Stacy, A. (2009). Understanding and Using: English Grammar (Edisi Keempat). United States of America: Pearson longman.

Gaya MLA

Betty, S.Azar., Stacy, A.Hagen. "Understanding and Using: English Grammar". Edisi Keempat United States of America: Pearson longman, 2009. Text.