@misc{indiciae50bdf9b1e6df,
  title = {Occurrences of alunite, pyrophyllite, and clays in the Cerro La Tiza area, Puerto Rico},
  author = {Fred Adelbert Hildebrand and Raymond J. Smith},
  year = {1959},
  doi = {10.3133/ofr5954},
  url = {https://pubs.usgs.gov/publication/ofr5954},
  note = {Source identifier: ofr5954}
}