4Hummels Ishii, Yi. The nature and growth of vertical specialization in world trade[ J]. Journal of International Economics, 2001,54 (1).
5Sanyal K, Jones R. The Theory of Trade in Middle Products[ J ]. American Economic Review, 1982,72( 1):16- 31
6Amdt Sven. Globalization and the Open Economy[ J]. North American Journal of Economics and Finance, 1997,8( 1 ):71 - 79.
7Feenstra R C, Hanson G H. Foreign Direct Investment and Relative Wages: Evidence from Mexico's Maquiladoras[ J]. Journal of International Economics, 1997, (42) : 371 - 394.
