@misc{indiciae19b888c22adc,
  title = {Geologic map of the Heath quadrangle, McCracken and Ballard Counties, Kentucky},
  author = {Wilds W. Olive},
  year = {1966},
  doi = {10.3133/gq561},
  url = {https://pubs.usgs.gov/publication/gq561},
  note = {Source identifier: gq561}
}