@misc{indiciae14acbcecd608,
  title = {Map showing thickness of overburden, Vienna Quadrangle, Virginia and Maryland},
  author = {Sherman K. Neuschel and A.J. Froelich},
  year = {1975},
  doi = {10.3133/ofr75520},
  url = {https://pubs.usgs.gov/publication/ofr75520},
  note = {Source identifier: ofr75520}
}