@misc{indiciae8eefdb5e0879,
  title = {Data set of world phosphate mines, deposits, and occurrences: Part A. Geologic data. Part B. Location and mineral economic data},
  author = {Carlotta B. Chernoff and G. J. Orris},
  year = {2002},
  doi = {10.3133/ofr02156},
  url = {https://pubs.usgs.gov/publication/ofr02156},
  note = {Source identifier: ofr02156}
}