@misc{indiciae40a6d6bbc0ba,
  title = {National Mineral-Resource Assessment: The 1996 estimate of undiscovered gold, silver, copper, lead, and zinc remaining in the United States},
  author = {Joseph A. Briskey and Paul G. Schruben},
  year = {1997},
  doi = {10.3133/70220355},
  url = {https://pubs.usgs.gov/publication/70220355},
  note = {Source identifier: 70220355}
}