APA (7th ed.) Citation

Azar, B. S., & Hagen, S. A. (2009). Understanding and using english grammar (Cuarta Edición.). Pearson Education.

Chicago Style (17th ed.) Citation

Azar, Betty S., and Stacy A. Hagen. Understanding and Using English Grammar. Cuarta Edición. [New York]: Pearson Education, 2009.

MLA (9th ed.) Citation

Azar, Betty S., and Stacy A. Hagen. Understanding and Using English Grammar. Cuarta Edición. Pearson Education, 2009.