@misc{indiciae675f52745f2f,
  title = {Digital geologic map of Yellowstone National Park, Idaho, Montana, and Wyoming and vicinity},
  author = {Robert L. Christiansen and Ronald R. Wahl},
  year = {1999},
  doi = {10.3133/ofr99174},
  url = {https://pubs.usgs.gov/publication/ofr99174},
  note = {Source identifier: ofr99174}
}