@misc{indiciaee2a8290d9223,
  title = {Geology and ore deposits of the Zimapan mining district, State of Hidalgo, Mexico},
  author = {F. S. Simons and E. Mapes},
  year = {1956},
  doi = {10.3133/pp284},
  url = {https://pubs.usgs.gov/publication/pp284},
  note = {Source identifier: pp284}
}