@misc{indiciae201a9ca5650a,
  title = {Mineral Commodity Summaries 2002},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {2002},
  doi = {10.3133/mineral2002},
  url = {https://pubs.usgs.gov/publication/mineral2002},
  note = {Source identifier: mineral2002}
}