@misc{indiciae38fb769f46a7,
  title = {Sulphur and pyrite},
  author = {R. W. Richards and J.H. Bridges},
  year = {1911},
  doi = {10.3133/b470j},
  url = {https://pubs.usgs.gov/publication/b470J},
  note = {Source identifier: b470J}
}