http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Nutrient trends and drivers in the Chesapeake Bay Watershed
University of Maryland Center for Environmental Science
1 online resource (4 unnumbered pages) : color illustrations, color maps.
Includes bibliographical references (page 4).
Fact sheet (Geological Survey (U.S.)) ; 2020-3069