@misc{indiciae530d9ded1cb9,
  title = {Vision based techniques for rotorcraft low altitude flight},
  author = {Sridhar, Banavar and Suorsa, Ray and Smith, Philip},
  year = {1991},
  url = {https://ntrs.nasa.gov/citations/19930065354},
  note = {Source identifier: 19930065354}
}