@misc{indiciaed9c174033dc0,
  title = {Detecting changes in the spatial distribution of nitrate contamination in ground water},
  author = {Z.-J. Liu and G.R. Hallberg and D.L. Zimmerman and R.D. Libra},
  year = {1997},
  url = {https://pubs.usgs.gov/publication/70019208},
  note = {Source identifier: 70019208}
}