@misc{indiciae59d696717c1a,
  title = {Geologic maps of the Jackson Purchase region, Kentucky},
  author = {W. W. Olive},
  year = {1980},
  doi = {10.3133/i1217},
  url = {https://pubs.usgs.gov/publication/i1217},
  note = {Source identifier: i1217}
}