@misc{indiciaeec7ab8c79cdd,
  title = {Fluorspar deposits in western Kentucky, part 1: Introduction},
  author = {James Steele Williams and Helen Duncan},
  year = {1955},
  doi = {10.3133/b1012a},
  url = {https://pubs.usgs.gov/publication/b1012A},
  note = {Source identifier: b1012A}
}