@misc{indiciaece8f5f05c479,
  title = {Determination of ash in coals unusually high in calcite and pyrite},
  author = {O.W. Rees and W.A. Selvig},
  year = {2002},
  doi = {10.1021/i560103a006},
  url = {https://pubs.usgs.gov/publication/70010996},
  note = {Source identifier: 70010996}
}