http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Concepts for a National Water-Quality Assessment Program
1 online resource (vii, 42 pages) : illustrations, maps.
by Robert M. Hirsch, William M. Alley, and William G. Wilber.
Includes bibliographical references (pages 39-42).
National Water-Quality Assessment Program (U.S.)
USGS National Water Quality Assessment Pilot Program.