@misc{indiciae079de93ed0f7,
  title = {Geology of the Williamson quadrangle in Kentucky},
  author = {Donald Clayton Alvord and Virgil A. Trent},
  year = {1962},
  doi = {10.3133/gq187},
  url = {https://pubs.usgs.gov/publication/gq187},
  note = {Source identifier: gq187}
}