@misc{indiciaeebd5ddd56bed,
  title = {Geologic map of the Mount Tyndall quadrangle, Custer County, Colorado},
  author = {M. R. Brock and Q. D. Singewald},
  year = {1968},
  doi = {10.3133/gq596},
  url = {https://pubs.usgs.gov/publication/gq596},
  note = {Source identifier: gq596}
}