@misc{indiciae948a75104d88,
  title = {Hydrologic Unit Map -- 1974, State of Michigan},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1974},
  doi = {10.3133/hu22},
  url = {https://pubs.usgs.gov/publication/hu22},
  note = {Source identifier: hu22}
}