@misc{indiciae5751dcdcd5cf,
  title = {Geologic map of the Poncha Springs SE quadrangle, Chaffee County, Colorado},
  author = {R. E. Van Alstine},
  year = {1970},
  doi = {10.3133/ofr70350},
  url = {https://pubs.usgs.gov/publication/ofr70350},
  note = {Source identifier: ofr70350}
}