http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Natural resource commodities--A century of statistics
prices, output, consumption, foreign trade, and employment in the United States, 1870-1973
Robert S. Manthy ; [edited by Joan R. Tron].
An update of Resources for the Future's Trends in natural resource commodities.