@misc{indiciae71faf93331ca,
  title = {Preliminary geologic map of the Duty Quadrangle, Virginia},
  author = {Charles R. Meissner},
  year = {1976},
  doi = {10.3133/ofr76161},
  url = {https://pubs.usgs.gov/publication/ofr76161},
  note = {Source identifier: ofr76161}
}