APA Style

Azar, B, S., Hagen, S, A. (2009). Understanding and Using English Grammar, 4th Edition. With Answer Key (4th. Edition). America: Pearson Logman.

MLA Style

Azar, Betty, S.., Hagen, Stacy, A.. "Understanding and Using English Grammar, 4th Edition. With Answer Key". 4th. Edition America: Pearson Logman, 2009. Koleksi Buku Teks.