@misc{indiciae74c3e86901ad,
  title = {Geology and coal resources of the Elk Valley area, Tennessee and Kentucky},
  author = {Kenneth John Englund},
  year = {1968},
  doi = {10.3133/pp572},
  url = {https://pubs.usgs.gov/publication/pp572},
  note = {Source identifier: pp572}
}