@misc{indiciae2530743f5bc3,
  title = {Geochemistry of the Cambrian-Ordovician aquifer system in the northern Midwest, United States: D in Regional aquifer-system analysis},
  author = {D. I. Siegel},
  year = {1989},
  doi = {10.3133/pp1405d},
  url = {https://pubs.usgs.gov/publication/pp1405D},
  note = {Source identifier: pp1405D}
}