APA (7th ed.) Citation

Krugman, P. R., Wells, R., & Olney, M. L. (2007). Essentials of economics (2. print.). Worth Publ.

Chicago Style (17th ed.) Citation

Krugman, Paul R., Robin Wells, and Martha L. Olney. Essentials of Economics. 2. print. New York: Worth Publ, 2007.

MLA (9th ed.) Citation

Krugman, Paul R., et al. Essentials of Economics. 2. print. Worth Publ, 2007.