@misc{indiciae967aeb144e27,
  title = {Defocus Measurement Using a Liquid Crystal Point Diffraction Interferometer},
  author = {Mercer, Carolyn R. and Creath, Katherine},
  year = {1994},
  url = {https://ntrs.nasa.gov/citations/19950006335},
  note = {Source identifier: 19950006335}
}