@misc{indiciae4aa04347ab87,
  title = {Contributions to economic geology, 1905: Gypsum and plasters},
  author = {C.E. Siebenthal},
  year = {1906},
  doi = {10.3133/b285k},
  url = {https://pubs.usgs.gov/publication/b285K},
  note = {Source identifier: b285K}
}