@misc{indiciae31bd49fc32ae,
  title = {Geology of the Argillite quadrangle, Kentucky},
  author = {Richard A. Sheppard and John C. Ferm},
  year = {1962},
  doi = {10.3133/gq175},
  url = {https://pubs.usgs.gov/publication/gq175},
  note = {Source identifier: gq175}
}