@misc{indiciae315c34038b52,
  title = {Preliminary map of copper provinces in the conterminous United States},
  author = {Edwin Wilson Tooker},
  year = {1980},
  doi = {10.3133/ofr79576d},
  url = {https://pubs.usgs.gov/publication/ofr79576D},
  note = {Source identifier: ofr79576D}
}