@misc{indiciaecd7ea301b0f8,
  title = {Phosphate deposits of the Concepcion del Oro district, Zacatecas, Mexico},
  author = {Cleaves Lincoln Rogers and Salvador Ulloa and Eugenio Tavera},
  year = {1952},
  doi = {10.3133/ofr52131},
  url = {https://pubs.usgs.gov/publication/ofr52131},
  note = {Source identifier: ofr52131}
}