APA (7th ed.) Citation

Green, S., & Wolf, I. K. (2015). Barron's GRE (21st edition.). Barron's.

Chicago Style (17th ed.) Citation

Green, Sharon, and Ira K. Wolf. Barron's GRE. 21st edition. Hauppauge, New York: Barron's, 2015.

MLA (9th ed.) Citation

Green, Sharon, and Ira K. Wolf. Barron's GRE. 21st edition. Barron's, 2015.

Warning: These citations may not always be 100% accurate.