@misc{indiciaebca2900be92e,
  title = {Mineral Commodity Summaries 2019},
  author = {U.S. Geological Survey},
  year = {2019},
  doi = {10.3133/70202434},
  url = {https://pubs.usgs.gov/publication/70202434},
  note = {Source identifier: 70202434}
}