@misc{indiciae99bdcab47d7f,
  title = {Mineral commodity summaries 2020},
  author = {U.S. Geological Survey},
  year = {2020},
  doi = {10.3133/mcs2020},
  url = {https://pubs.usgs.gov/publication/mcs2020},
  note = {Source identifier: mcs2020}
}