http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Nitrate concentrations, 1936-99, and pesticide concentrations, 1990-99, in the unconfined aquifer in the San Luis Valley, Colorado
National Water-Quality Assessment Program (U.S.)
1 online resource (vi, 12 pages) : illustrations, color maps.
"National Water-Quality Assessment Program."
GPO Cataloging Record Distribution Program (CRDP).
Includes bibliographical references (pages 11-12).
Water-resources investigations report ; 01-4131