APA (7th ed.) Citation

Kolby, J. (2009). GMAT data sufficiency prep course. Nova Press.

Chicago Style (17th ed.) Citation

Kolby, Jeff. GMAT Data Sufficiency Prep Course. Los Angeles, Calif: Nova Press, 2009.

MLA (9th ed.) Citation

Kolby, Jeff. GMAT Data Sufficiency Prep Course. Nova Press, 2009.

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