@misc{indiciae50628108ea5d,
  title = {Contributions to economic geology, 1912; Part I, Metals and nonmetals except fuels-Lead and Zinc},
  author = {Frank Cathcart Calkins and E. L. Jones and Joseph Bertram Umpleby},
  year = {1914},
  doi = {10.3133/b540e},
  url = {https://pubs.usgs.gov/publication/b540E},
  note = {Source identifier: b540E}
}