@misc{indiciae15a29873b744,
  title = {Geologic map and lignite resources of the Cussicks Spring quadrangle, Williams County, North Dakota},
  author = {John M. Spencer},
  year = {1981},
  doi = {10.3133/coal89},
  url = {https://pubs.usgs.gov/publication/coal89},
  note = {Source identifier: coal89}
}