@misc{indiciaee4f9937db55f,
  title = {The Twentymile Park district of the Yampa coal field, Routt County, Colorado},
  author = {Marius R. Campbell},
  year = {1923},
  doi = {10.3133/b748},
  url = {https://pubs.usgs.gov/publication/b748},
  note = {Source identifier: b748}
}