APA Edition Citation

Kolby, J., Vaughn, D., & Vamsidhar, K. (2013). GMAT: Data sufficiency prep course. Nova Press.

Chicago Edition Citation

Kolby, Jeff, Derrick Vaughn, and Kunda Vamsidhar. GMAT: Data Sufficiency Prep Course. West Hollywood: Nova Press, 2013.

MLA Edition Citation

Kolby, Jeff, et al. GMAT: Data Sufficiency Prep Course. Nova Press, 2013.