@misc{indiciae18d38a2a5f39,
  title = {Map showing mineral resources of the Culpeper Basin, Virginia and Maryland availability and planning for future needs},
  author = {A.J. Froelich and B. D. Leavy},
  year = {1982},
  doi = {10.3133/i1313b},
  url = {https://pubs.usgs.gov/publication/i1313B},
  note = {Source identifier: i1313B}
}