@misc{indiciae619b95bc59c3,
  title = {Hydrologic Unit Map -- 1974, Minnesota},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1974},
  doi = {10.3133/hu23},
  url = {https://pubs.usgs.gov/publication/hu23},
  note = {Source identifier: hu23}
}