@misc{indiciaeaa18a292a6eb,
  title = {A millimeter wave technique for measuring ice thickness on the Space Shuttle's external tank},
  author = {Kendra, John E. and Ulaby, Fawwaz T. and Wu, Steve},
  year = {1991},
  url = {https://ntrs.nasa.gov/citations/19920034585},
  note = {Source identifier: 19920034585}
}