http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Selected findings and current perspectives on urban and agricultural water quality by the National Water-Quality Assessment Program
Also available via Internet from the USGS web site (PDF version). Address as of 6/29/01: http://water.usgs.gov/pubs/FS/fs-047-01/pdf/fs047-01.pdf; current access is available via PURL.
National Water-Quality Assessment Program (U.S.)
Fact sheet (Geological Survey (U.S.)) ; FS-01-047