@misc{indiciae2597391cd57e,
  title = {Mine maps of the Cripple Creek district, Colorado},
  author = {A. H. Koschmann and G. F. Loughlin},
  year = {1965},
  doi = {10.3133/ofr6590},
  url = {https://pubs.usgs.gov/publication/ofr6590},
  note = {Source identifier: ofr6590}
}