@misc{indiciae3ec8642f8d1a,
  title = {The Book Cliffs coal field in Garfield and Mesa counties, Colorado},
  author = {Charles Edgar Erdmann},
  year = {1934},
  doi = {10.3133/b851},
  url = {https://pubs.usgs.gov/publication/b851},
  note = {Source identifier: b851}
}