@misc{indiciae40610933588c,
  title = {Geologic map of the Blackford quadrangle, western Kentucky},
  author = {Dewey Harold Amos},
  year = {1970},
  doi = {10.3133/gq873},
  url = {https://pubs.usgs.gov/publication/gq873},
  note = {Source identifier: gq873}
}