@misc{indiciaec9b50e5a7ad0,
  title = {A data base of nitrate in ground-water samples from the conterminous United States},
  author = {K.J. Lanfear},
  year = {1992},
  doi = {10.3133/ofr92652},
  url = {https://pubs.usgs.gov/publication/ofr92652},
  note = {Source identifier: ofr92652}
}