@misc{indiciae739f0419d932,
  title = {Preliminary geologic map of the Soldier quadrangle, northeastern Kentucky},
  author = {John Calvin Philley and David Kent Hylbert and Harry P. Hoge},
  year = {1975},
  doi = {10.3133/ofr75151},
  url = {https://pubs.usgs.gov/publication/ofr75151},
  note = {Source identifier: ofr75151}
}