@misc{indiciae2f928d7a35c0,
  title = {Preliminary map of fluorine provinces in the conterminous United States},
  author = {Ralph Erskine Van Alstine and Edwin Wilson Tooker},
  year = {1979},
  doi = {10.3133/ofr79576g},
  url = {https://pubs.usgs.gov/publication/ofr79576G},
  note = {Source identifier: ofr79576G}
}