@misc{indiciae3295909d13c1,
  title = {The mining districts of the Western United States},
  author = {James M. Hill and Waldemar Lindgren},
  year = {1912},
  doi = {10.3133/b507},
  url = {https://pubs.usgs.gov/publication/b507},
  note = {Source identifier: b507}
}