@misc{indiciaeb7bafed1363c,
  title = {Coal resource occurrence and coal development potential maps of the Poker Jim Butte quadrangle, Rosebud and Powder River Counties, Montana},
  author = {W. J. Mapel and B. K. Martin and B. A. Butler},
  year = {1978},
  doi = {10.3133/ofr78651},
  url = {https://pubs.usgs.gov/publication/ofr78651},
  note = {Source identifier: ofr78651}
}