TY  - RPRT
TI  - Nitrate in groundwater of the midwestern United States: A regional investigation on relations to land use and soil properties
AU  - D. Kolpin
AU  - M. Burkart
AU  - D. Goolsby
PY  - 1999
UR  - https://pubs.usgs.gov/publication/70020921
ID  - 70020921
ER  -