http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
occupational statistics of the 1930 census tabulated by class of work and industry, as well as by sex, race, and age groups
Occupational statistics of the 1930 census
Prepared by W. S. Woytinsky for the Committee on Social Security of the Social Science Research Council.