@misc{indiciaec18272997e9c,
  title = {Anthracite-Crested Butte folio, Colorado},
  author = {Samuel Franklin Emmons and Whitman Cross and George H. Eldridge},
  year = {1894},
  doi = {10.3133/gf9},
  url = {https://pubs.usgs.gov/publication/gf9},
  note = {Source identifier: gf9}
}