@misc{indiciae9a6949b6ccdf,
  title = {Geochemistry of a Tertiary sedimentary phosphate deposit: Baja California Sur, Mexico},
  author = {D.Z. Piper},
  year = {1991},
  doi = {10.1016/0009-2541(91)90075-3},
  url = {https://pubs.usgs.gov/publication/70016478},
  note = {Source identifier: 70016478}
}