@misc{indiciae9b8d634bc9de,
  title = {Mineral resources of the United States, 1917: Part II - Nonmetals},
  author = {Hiram Dryer McCaskey and Gerald Francis Loughlin},
  year = {1920},
  doi = {10.3133/70175822},
  url = {https://pubs.usgs.gov/publication/70175822},
  note = {Source identifier: 70175822}
}