Cita APA (7a ed.)

Helpman, E., & Krugman, P. R. (1986). Market structure and foreign trade: Increasing returns, imperfect competition, and the international economy ([2nd printing].). MIT Press.

Cita Chicago Style (17a ed.)

Helpman, Elhanan, y Paul R. Krugman. Market Structure and Foreign Trade: Increasing Returns, Imperfect Competition, and the International Economy. [2nd printing]. Cambridge, Mass. [etc.]: MIT Press, 1986.

Cita MLA (9a ed.)

Helpman, Elhanan, y Paul R. Krugman. Market Structure and Foreign Trade: Increasing Returns, Imperfect Competition, and the International Economy. [2nd printing]. MIT Press, 1986.