APA (7th ed.) Citation

Helpman, E., & Krugman, P. R. (1991). Market structure and foreign trade: Increasing returns, imperfect competition, and the international economy (4. print.). MIT Press.

Chicago Style (17th ed.) Citation

Helpman, Elhanan, and Paul R. Krugman. Market Structure and Foreign Trade: Increasing Returns, Imperfect Competition, and the International Economy. 4. print. Cambridge, Mass. [u.a.]: MIT Press, 1991.

MLA (9th ed.) Citation

Helpman, Elhanan, and Paul R. Krugman. Market Structure and Foreign Trade: Increasing Returns, Imperfect Competition, and the International Economy. 4. print. MIT Press, 1991.