@misc{indiciae8025840e299c,
  title = {Geologic map of the Verona quadrangle, north-central Kentucky},
  author = {W. C. Swadley},
  year = {1969},
  doi = {10.3133/gq819},
  url = {https://pubs.usgs.gov/publication/gq819},
  note = {Source identifier: gq819}
}