@misc{indiciae9de5a168c23b,
  title = {Geologic map and coal resources of the Thompson Creek area, Big Horn County, Montana},
  author = {W. J. Mapel and J.K. Griffith},
  year = {1981},
  doi = {10.3133/mf1312},
  url = {https://pubs.usgs.gov/publication/mf1312},
  note = {Source identifier: mf1312}
}