@misc{indiciae2d741f46cc9a,
  title = {The international phosphate resource data base; development and maintenance},
  author = {Nancy J. Bridges},
  year = {1983},
  doi = {10.3133/ofr83490},
  url = {https://pubs.usgs.gov/publication/ofr83490},
  note = {Source identifier: ofr83490}
}