@misc{indiciaee6589f841a43,
  title = {Ground-water levels in the United States, 1967-71, north-central States},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1973},
  doi = {10.3133/wsp2090},
  url = {https://pubs.usgs.gov/publication/wsp2090},
  note = {Source identifier: wsp2090}
}