@misc{indiciae78e84ea274a7,
  title = {Phosphate deposits of the United States},
  author = {George R. Mansfield},
  year = {1940},
  doi = {10.2113/gsecongeo.35.3.405},
  url = {https://pubs.usgs.gov/publication/70213445},
  note = {Source identifier: 70213445}
}