@misc{indiciae106be27fe194,
  title = {Preliminary map of phosphorous provinces in the conterminous United States},
  author = {James Bachelder Cathcart and Edwin Wilson Tooker},
  year = {1979},
  doi = {10.3133/ofr79576a},
  url = {https://pubs.usgs.gov/publication/ofr79576A},
  note = {Source identifier: ofr79576A}
}