@misc{indiciae432d20a4c36e,
  title = {Water-quality indicators in the Prairie du Chien-Jordan Aquifer, southeastern Minnesota},
  author = {Shannon E. Smith},
  year = {1991},
  doi = {10.3133/ofr91480},
  url = {https://pubs.usgs.gov/publication/ofr91480},
  note = {Source identifier: ofr91480}
}