APA (7th ed.) Citation

Krugman, P. R., Obstfeld, M., & Melitz, M. J. (2012). International economics: Theory & policy (9. ed.). Addison-Wesley.

Chicago Style (17th ed.) Citation

Krugman, Paul R., Maurice Obstfeld, and Marc J. Melitz. International Economics: Theory & Policy. 9. ed. Boston [u.a.]: Addison-Wesley, 2012.

MLA (9th ed.) Citation

Krugman, Paul R., et al. International Economics: Theory & Policy. 9. ed. Addison-Wesley, 2012.