@misc{indiciaef243cb68c580,
  title = {Investigations of the principal fluorspar districts of Mexico},
  author = {Ralph Erskine Van Alstine and Samuel Estrada and Ernesto de la Garza},
  year = {1963},
  doi = {10.3133/ofr63124},
  url = {https://pubs.usgs.gov/publication/ofr63124},
  note = {Source identifier: ofr63124}
}