TY  - RPRT
TI  - Risk of nitrate in groundwaters of the United States - A national perspective
AU  - B. T. Nolan
AU  - B. C. Ruddy
AU  - K.J. Hitt
AU  - D.R. Helsel
PY  - 1997
DO  - 10.1021/es960818d
UR  - https://pubs.usgs.gov/publication/70019648
ID  - 70019648
ER  -