@misc{indiciae44e7e2b91785,
  title = {Hydrology of the Great Plains aquifer system in Nebraska, Colorado, Kansas, and adjacent areas},
  author = {J. O. Helgesen and R. B. Leonard and R. J. Wolf},
  year = {1993},
  doi = {10.3133/pp1414e},
  url = {https://pubs.usgs.gov/publication/pp1414E},
  note = {Source identifier: pp1414E}
}