http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Old-age, survivor, disability insurance beneficiaries by ZIP code area
VII. Kansas City Region -- IX. San Francisco Region.
Social Security Administration, Office of Policy, Office of Research and Statistics.
Books are divided by region (i.e. book VII is for the Kansas City Region).