@misc{indiciae71ac923f9eec,
  title = {Optical tip clearance sensor for aircraft engine controls},
  author = {Poppel, G. L. and Marple, D. T. F. and Baumbick, R. J.},
  year = {1982},
  url = {https://ntrs.nasa.gov/citations/19820054156},
  note = {Source identifier: 19820054156}
}