Branson, William H., and Helen Junz. "Trends in U.S. Trade and Comparative Advantage."Brookings Papers on Economic Activity, no. 2, 1971, pp. 285–345.
"Comparative Advantage." Economics Online, n.d.
"Comparative Advantage and the Benefits of Trade." Library of Economics and Liberty, n.d.
Henderson, David R. "Opportunity Cost: The Concise Encyclopedia of Economics." Library of Economics and Liberty, n.d.
Suranovic, Steven M. "The Theory Of Comparative Advantage – Overview." International Trade Theory and Policy, n.d.