@misc{indiciaedc3404644c04,
  title = {Geologic map showing the thickness and structure of the Anderson-Wyodak coal bed in the north half of the Powder River Basin, southeastern Montana and northeastern Wyoming},
  author = {N.M. Denson and C. T. Pierson},
  year = {1991},
  doi = {10.3133/i2094a},
  url = {https://pubs.usgs.gov/publication/i2094A},
  note = {Source identifier: i2094A}
}