@misc{indiciae2af0108cc38b,
  title = {Noncontaminating method for visualizing gas flow},
  author = {Stepka, F. S. and Poferl, D. and Goldstein, R. J.},
  year = {1976},
  url = {https://ntrs.nasa.gov/citations/19760000088},
  note = {Source identifier: 19760000088}
}