8T. W. Schultz, Investment in Human Capital, American Economic Review, March, 1961, pp.l-17; G. Becker, Investment in Human Capital: A Theoretical Analysis, supplement to Journal of Political Economy, October 1962.
9M. V. Bosner, International Trade and Technical Change, Oxford Economic Papers, 1961, pp.323-341.
10Raymond Vernon, International Investment and International Trade in the Product Cycle, Quarterly Journal of Economics, May 1966 , pp.197-207.