@misc{indiciae9fad58e15fed,
  title = {Digital mining claim density map for Federal lands in the Pacific Northwest},
  author = {Harry W. Campbell and Paul C. Hyndman},
  year = {1996},
  doi = {10.3133/ofr96737},
  url = {https://pubs.usgs.gov/publication/ofr96737},
  note = {Source identifier: ofr96737}
}