@misc{indiciae846feb0ac2ec,
  title = {Preliminary map showing the location of productive lode and placer gold mines in Montana (with explanatory text)},
  author = {David Frishman and J. E. Elliott and E.E. Foord and R. C. Pearson and W. H. Raymond},
  year = {1990},
  doi = {10.3133/ofr90241},
  url = {https://pubs.usgs.gov/publication/ofr90241},
  note = {Source identifier: ofr90241}
}