The Natural Resource Content of Foreign Trade, 1870-1955, and the Relative Abundance of Natural Resources in the United States
Jaroslav Vanek, The Natural Resource Content of Foreign Trade, 1870-1955, and the Relative Abundance of Natural Resources in the United States, The Review of Economics and Statistics, Vol. 41, No. 2, Part 1 (May, 1959), pp. 146-153