Citazione Stile APA (7a Edizione)

Helpman, E., & Krugman, P. R. (1985). Market structure and foreign trade: Increasing returns, imperfect competition, and the international economy. MIT Press.

Citazione stile Chigago Style (17a edizione)

Helpman, Elhanan, e Paul R. Krugman. Market Structure and Foreign Trade: Increasing Returns, Imperfect Competition, and the International Economy. Cambridge, Mass.: MIT Press, 1985.

Citatione MLA (9a ed.)

Helpman, Elhanan, e Paul R. Krugman. Market Structure and Foreign Trade: Increasing Returns, Imperfect Competition, and the International Economy. MIT Press, 1985.