@misc{indiciaefef502a9fcf2,
  title = {Quality of economically extractable coal beds in the Gillette coal field as compared with other Tertiary coal beds in the Powder River basin, Wyoming and Montana},
  author = {Margaret S. Ellis},
  year = {2002},
  doi = {10.3133/ofr02174},
  url = {https://pubs.usgs.gov/publication/ofr02174},
  note = {Source identifier: ofr02174}
}