@misc{indiciaef2e8d753360c,
  title = {Cross‐hole radar attenuation tomography using a frequency centroid down‐shift method: Consideration of non‐linear frequency dependence of EM wave attenuation},
  author = {Lanbo Liu and Chaoguang Zhou and John W. Lane and F.P. Haeni},
  year = {1997},
  url = {https://pubs.usgs.gov/publication/70206379},
  note = {Source identifier: 70206379}
}