http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Improvements to the DRASTIC ground-water vulnerability mapping method
National Water-Quality Assessment Program (U.S.)
Title from PDF title screen (viewed on August 27, 2004).
"National Water-Quality Assessment Program--NAWQA."
Title from PDF title screen (viewed Aug. 27, 2004).
At head of title: National Water-Quality Assessment Program--NAWQA.
Mode of access: Internet from the USGS Web site. Address as of 8/27/04: http://id.water.usgs.gov/PDF/factsheet/DRASTIC.pdf ; current access is available via PURL.
Fact sheet (Geological Survey (U.S.)) ; FS-99-066