@misc{indiciaeeff43c4120ed,
  title = {U-Pb ages of uraniferous opals and implications for the history of beryllium, fluorine, and uranium mineralization at Spor Mountain, Utah},
  author = {K.R. Ludwig and D. A. Lindsey and R. A. Zielinski and K. R. Simmons},
  year = {1980},
  doi = {10.1016/0012-821x(80)90008-4},
  url = {https://pubs.usgs.gov/publication/70012396},
  note = {Source identifier: 70012396}
}