@misc{indiciae4308565087cf,
  title = {Hydrologic Unit Map-1974, State of Illinois},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1975},
  doi = {10.3133/hu13},
  url = {https://pubs.usgs.gov/publication/hu13},
  note = {Source identifier: hu13}
}