@misc{indiciae8804ea5a0d61,
  title = {Chemical and mineralogical analyses of coal-bearing strata in the Appalachian Basin},
  author = {Frank T. Dulong and Nick Fedorko and John J. Renton and C. Blaine Cecil},
  year = {2002},
  doi = {10.3133/ofr02489},
  url = {https://pubs.usgs.gov/publication/ofr02489},
  note = {Source identifier: ofr02489}
}