@misc{indiciae0b46d957eb4f,
  title = {Geologic map of the Oak Forest Quadrangle and part of the Blacksville Quadrangle, southwestern Pennsylvania},
  author = {J.B. Roen},
  year = {1972},
  doi = {10.3133/i699},
  url = {https://pubs.usgs.gov/publication/i699},
  note = {Source identifier: i699}
}