@misc{indiciaeb6578480dc8a,
  title = {Principal facts and complete Bouguer gravity anomaly map for the west half of the Butte 1° x 2 ° quadrangle, Montana},
  author = {Jerry H. Hassemer},
  year = {1981},
  doi = {10.3133/ofr81949},
  url = {https://pubs.usgs.gov/publication/ofr81949},
  note = {Source identifier: ofr81949}
}