@misc{indiciae863bdc3dbe2d,
  title = {Preliminary digital model of ground-water flow in the Madison Group, Powder River Basin and adjacent areas, Wyoming, Montana, South Dakota, North Dakota, and Nebraska},
  author = {Leonard F. Konikow},
  year = {1976},
  doi = {10.3133/wri7563},
  url = {https://pubs.usgs.gov/publication/wri7563},
  note = {Source identifier: wri7563}
}