@misc{indiciae4f1fa82a889d,
  title = {Mineral Commodity Summaries 1999},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1999},
  doi = {10.3133/mineral1999},
  url = {https://pubs.usgs.gov/publication/mineral1999},
  note = {Source identifier: mineral1999}
}