APA (7th ed.) Zitazioa

Krugman, P. R., & Obstfeld, M. (1991). International economics: Theory and policy (2nd ed.). Harper Collins.

Chicago Style (17th ed.) Zitazioa

Krugman, Paul R., eta Maurice Obstfeld. International Economics: Theory and Policy. 2nd ed. New York: Harper Collins, 1991.

MLA (9th ed.) Zitazioa

Krugman, Paul R., eta Maurice Obstfeld. International Economics: Theory and Policy. 2nd ed. Harper Collins, 1991.