@misc{indiciaebad60e5f6c65,
  title = {Hydrologic Unit Map -- 1974, state of Arkansas},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1977},
  doi = {10.3133/hu4},
  url = {https://pubs.usgs.gov/publication/hu4},
  note = {Source identifier: hu4}
}