@misc{indiciae0c3f0a6dbf08,
  title = {Overview of the National Water-Quality Assessment Program},
  author = {P.P. Leahy and T. H. Thompson},
  year = {1994},
  doi = {10.3133/ofr9470},
  url = {https://pubs.usgs.gov/publication/ofr9470},
  note = {Source identifier: ofr9470}
}