@misc{indiciae8220f53b4b94,
  title = {Geologic map of the Union quadrangle, Boone County, Kentucky},
  author = {W. C. Swadley},
  year = {1969},
  doi = {10.3133/gq779},
  url = {https://pubs.usgs.gov/publication/gq779},
  note = {Source identifier: gq779}
}