@misc{indiciae15946dd36963,
  title = {Mineral commodity summaries 2015},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {2015},
  doi = {10.3133/70140094},
  url = {https://pubs.usgs.gov/publication/70140094},
  note = {Source identifier: 70140094}
}