1Balassa, B. , 1967. Trade Liberalization A- mong Industrial Countries, McGraw - Hill, New York.
2Hummels, D. , Rapoport, D. and Yi, K. - M. , 1998. Vertical specialization and the changing nature of world trade. Federal Reserve Bank of New York Economic Policy Review June, pp. 79 - 99.
3Krugman, P. R. , 1995. Growing world trade : causes and consequences. Brookings Papers on Economic Activity 1, pp. 327 - 377.
4Ohlin, B., 1933. International and interre-gional trade, Harvard University Press, Cambridge, MA.
