@misc{indiciaea784a7ef8399,
  title = {Geologic map and lignite resources of the Clark Butte NE quadrangle, North Dakota},
  author = {G. D. Mowat},
  year = {1980},
  doi = {10.3133/coal86},
  url = {https://pubs.usgs.gov/publication/coal86},
  note = {Source identifier: coal86}
}