@misc{indiciaee3c9ff964c2d,
  title = {Coal resource occurrence and coal development potential maps of the Volborg Quadrangle, Custer and Powder River counties, Montana},
  author = {Colorado School of Mines Research Institute},
  year = {1979},
  doi = {10.3133/ofr7919},
  url = {https://pubs.usgs.gov/publication/ofr7919},
  note = {Source identifier: ofr7919}
}