@misc{indiciae6e5f57e42e32,
  title = {The Permian phosphorite deposits of western United States},
  author = {Vincent Ellis McKelvey and Roger Warren Swanson and Richard Porter Sheldon},
  year = {1952},
  doi = {10.3133/tei263},
  url = {https://pubs.usgs.gov/publication/tei263},
  note = {Source identifier: tei263}
}