@misc{indiciaec0190b01c763,
  title = {Thickness of overburden map, Annandale Quadrangle, Virginia},
  author = {A.J. Froelich},
  year = {1975},
  doi = {10.3133/ofr75153},
  url = {https://pubs.usgs.gov/publication/ofr75153},
  note = {Source identifier: ofr75153}
}