@misc{indiciae0e08875ea495,
  title = {Summary of the geology, mineral resources, landscape geochemistry, and engineering geologic characteristics of the northern Powder River coal region, Montana: Engineering geologic characteristics},
  year = {1977},
  doi = {10.3133/ofr77292c},
  url = {https://pubs.usgs.gov/publication/ofr77292C},
  note = {Source identifier: ofr77292C}
}