1Helpman, Elhanan and Paul R. Krugman, "Trade Policy and Market Structure", Cambridge, MA:The MIT Press, 1989.
2Krugman, Paul R. ,“Import Protection as Export Promotion: International Competition in the Presence of Oligopoly and Economies of Scale ,” In Henryk Kierzkowski ( ed. ) , Monopolistic Competition in International Trade. Oxford: Oxford University Press, 1984, pp. 180 - 193.
3Krugman, Paul R. , "Increasing Returns, Monopolistic Competition, and International Trade", Journal of International Economics, 9: 1979, pp. 469-479.
4Leontief, Wassily, "Studies in the Structure of the American Economy", New York: Oxford University Press, 1953.
