@misc{indiciae9c06d9110cde,
  title = {Geologic map of parts of the Benham and Appalachia quadrangles, Harlan and Letcher Counties, Kentucky},
  author = {A.J. Froelich and Byron D. Stone},
  year = {1973},
  doi = {10.3133/gq1059},
  url = {https://pubs.usgs.gov/publication/gq1059},
  note = {Source identifier: gq1059}
}