@misc{indiciaebe45c6c4ad49,
  title = {Historical Statistics for Mineral Commodities in the United States},
  author = {Thomas Kelly and David Buckingham and Carl A. DiFrancesco and Kenneth E. Porter and Thomas G. Goonan and John L. Sznopek and Cyrus Berry and Melissa Crane},
  year = {2001},
  doi = {10.3133/ofr20016},
  url = {https://pubs.usgs.gov/publication/ofr20016},
  note = {Source identifier: ofr20016}
}