@misc{indiciae17873270ba89,
  title = {Seismic refraction survey of the pre-Cretaceous basement surface near the inner edge of the coastal plain in Stafford and King George Counties, Virginia},
  author = {Hans D. Ackermann and Muriel S. Grim},
  year = {1977},
  doi = {10.3133/ofr77480},
  url = {https://pubs.usgs.gov/publication/ofr77480},
  note = {Source identifier: ofr77480}
}