@misc{indiciae1e163336cc9f,
  title = {Geology of the Elva quadrangle, Kentucky},
  author = {Wilds W. Olive},
  year = {1963},
  doi = {10.3133/gq230},
  url = {https://pubs.usgs.gov/publication/gq230},
  note = {Source identifier: gq230}
}