@misc{indiciaefc6d35a9c905,
  title = {Determining the fusain content of illinois coals. A comparison of chemical and petrographic methods},
  author = {B.C. Parks and G.W. Land and O.W. Rees},
  year = {2002},
  doi = {10.1021/i560104a008},
  url = {https://pubs.usgs.gov/publication/70011061},
  note = {Source identifier: 70011061}
}