@misc{indiciae27f1f0406aab,
  title = {Map showing localities and amounts of metallic mineral production in Colorado},
  author = {William R. Marsh and Roberta W. Queen},
  year = {1974},
  doi = {10.3133/mr58},
  url = {https://pubs.usgs.gov/publication/mr58},
  note = {Source identifier: mr58}
}