@misc{indiciaef29ea23fb376,
  title = {Analysis, design, fabrication and testing of an optical tip clearance sensor},
  author = {Poppel, G. L. and Marple, D. T. F. and Kingsley, J. D.},
  year = {1981},
  url = {https://ntrs.nasa.gov/citations/19830002857},
  note = {Source identifier: 19830002857}
}