@misc{indiciae3992b2cf2209,
  title = {Illinois ground-water quality},
  author = {D. C. Voelker and R.P. Clarke},
  year = {1987},
  doi = {10.3133/ofr87723},
  url = {https://pubs.usgs.gov/publication/ofr87723},
  note = {Source identifier: ofr87723}
}