@misc{indiciaea5b1dfd6fe90,
  title = {Ryan model 520 radar altimeter Final engineering report},
  author = {Hoffman, H. T. and Olthoff, N. L.},
  year = {1963},
  url = {https://ntrs.nasa.gov/citations/19660015198},
  note = {Source identifier: 19660015198}
}