@misc{indiciae458d3473027b,
  title = {Geologic map of the Roxana 7 1/2-minute Quadrangle, Letcher and Harlan counties, Kentucky},
  author = {Edwin K. Maughan},
  year = {1976},
  doi = {10.3133/ofr76156},
  url = {https://pubs.usgs.gov/publication/ofr76156},
  note = {Source identifier: ofr76156}
}