@misc{indiciae1991ae5621cc,
  title = {Cross-well radar in layered sediments},
  author = {K.J. Ellefsen},
  year = {1996},
  doi = {10.3133/ofr96510},
  url = {https://pubs.usgs.gov/publication/ofr96510},
  note = {Source identifier: ofr96510}
}