@misc{indiciae633d3d1840fb,
  title = {Corundum and its occurrence and distribution in the United States (a revised and enlarged edition of Bulletin 180)},
  author = {Joseph Hyde Pratt},
  year = {1906},
  doi = {10.3133/b269},
  url = {https://pubs.usgs.gov/publication/b269},
  note = {Source identifier: b269}
}