@misc{indiciae0b80aae1e092,
  title = {Undiscovered deposits of gold, silver, copper, lead, and zinc in the conterminous United States},
  author = {Richard B. McCammon},
  year = {1997},
  doi = {10.3133/fs18995},
  url = {https://pubs.usgs.gov/publication/fs18995},
  note = {Source identifier: fs18995}
}