@misc{indiciaeaff15d8d81ab,
  title = {Philipsburg folio, Montana},
  author = {Frank C. Calkins and William Harvey Emmons},
  year = {1915},
  doi = {10.3133/gf196},
  url = {https://pubs.usgs.gov/publication/gf196},
  note = {Source identifier: gf196}
}