@misc{indiciae86982c2d54b7,
  title = {Digital mine claim density map for Federal lands in Montana, 1996},
  author = {Harry W. Campbell and Paul C. Hyndman},
  year = {1998},
  doi = {10.3133/ofr98489},
  url = {https://pubs.usgs.gov/publication/ofr98489},
  note = {Source identifier: ofr98489}
}