http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
preliminary list of references for the history of agricultural science and technology in the United States
compiled and edited by Carroll W. Pursell, Jr. and Earl M. Rogers.
"A cooperative project by the Agricultural History Branch, Economic Research Service, U.S. Dept. of Agriculture and the Agricultural History Center."