@misc{indiciaeae1b55890684,
  title = {Data base for a national mineral-resource assessment of undiscovered deposits of gold, silver, copper, lead, and zinc in the conterminous United States},
  author = {S. D. Ludington and D. P. Cox and R.B. McCammon},
  year = {1996},
  doi = {10.3133/ofr9696},
  url = {https://pubs.usgs.gov/publication/ofr9696},
  note = {Source identifier: ofr9696}
}