@misc{indiciaeb4f9fd14b3cd,
  title = {Geologic map of the Hunter-Fryingpan Wilderness Area and the Porphyry Mountain Wilderness Study Area, Pitkin County, Colorado},
  author = {Steve Ludington and R. A. Yeoman},
  year = {1980},
  doi = {10.3133/mf1236a},
  url = {https://pubs.usgs.gov/publication/mf1236A},
  note = {Source identifier: mf1236A}
}