Humphrey, Thomas M. "Changing Views of Comparative Advantage," in Federal Reserve Bank of Richmond. "July 1972, Vol. 58 , No. 7," Economic Quarterly (Federal Reserve Bank of Richmond) (July 1972) : 9-15. https://fraser.stlouisfed.org/title/960/item/37536/toc/33598 , accessed on April 25, 2024.