@misc{indiciaea62a19822a3a,
  title = {Applicability of the diffusion approximation},
  author = {Biryukov, Y. L. and Titarchuk, L. G. and Chesnokov, Y. M.},
  year = {1974},
  url = {https://ntrs.nasa.gov/citations/19750003356},
  note = {Source identifier: 19750003356}
}