@misc{indiciae03da25ffa0f3,
  title = {Mineral Commodity Summaries 2007},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {2007},
  doi = {10.3133/mineral2007},
  url = {https://pubs.usgs.gov/publication/mineral2007},
  note = {Source identifier: mineral2007}
}