Cita APA (7a ed.)

Helpman, E., & Krugman, P. R. (1993). Market structure and foreign trade. Increasing returns, imperfect competition, and the international economy (5th edition.). 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. 5th edition. Cambridge: MIT Press, 1993.

Cita MLA (8a ed.)

Helpman, Elhanan, y Paul R. Krugman. Market Structure and Foreign Trade. Increasing Returns, Imperfect Competition, and the International Economy. 5th edition. MIT Press, 1993.