@misc{indiciae26560a4edec5,
  title = {Heat trap - An optimized far infrared field optics system},
  author = {Harper, D. A. and Hildebrand, R. H. and Winston, R. and Stiening, R.},
  year = {1976},
  url = {https://ntrs.nasa.gov/citations/19760036242},
  note = {Source identifier: 19760036242}
}