@misc{indiciaeb2c29a1bab43,
  title = {Numerical calculations on a wide angle filter lens.},
  author = {Den Boer, J. A. and Wilska, A. P.},
  year = {1965},
  url = {https://ntrs.nasa.gov/citations/19660032209},
  note = {Source identifier: 19660032209}
}