@misc{indiciaef7d25a781fae, title = {Mineral Commodity Summaries 2001}, author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey}, year = {2001}, doi = {10.3133/mineral2001}, url = {https://pubs.usgs.gov/publication/mineral2001}, note = {Source identifier: mineral2001} }