@misc{indiciae66df1f6c444f,
  title = {Variation of organic sulfur in macerals of selected Illinois Basin coals},
  author = {I. Demir and R.D. Harvey},
  year = {1991},
  doi = {10.1016/0146-6380(91)90116-2},
  url = {https://pubs.usgs.gov/publication/70014930},
  note = {Source identifier: 70014930}
}