@misc{indiciaec6e996579f09,
  title = {Digital mining claim density map for federal lands in Colorado: 1996},
  author = {Paul C. Hyndman and Harry W. Campbell},
  year = {1999},
  doi = {10.3133/ofr99410},
  url = {https://pubs.usgs.gov/publication/ofr99410},
  note = {Source identifier: ofr99410}
}