@misc{indiciae084f2833ba96,
  title = {Coal assessments and coal research in the Appalachian basin},
  author = {Susan J. Tewalt and Leslie F. Ruppert},
  year = {2014},
  doi = {10.3133/pp1708d.4},
  url = {https://pubs.usgs.gov/publication/pp1708D.4},
  note = {Source identifier: pp1708D.4}
}