@misc{indiciae58ad7a1aec0a,
  title = {Photogeologic and reconnaissance geologic map of the Forty Creek Quadrangle, Custer County, Montana},
  author = {S. J. Luft and D.H. Meier},
  year = {1987},
  doi = {10.3133/mf1969},
  url = {https://pubs.usgs.gov/publication/mf1969},
  note = {Source identifier: mf1969}
}