@misc{indiciae027fe28cfc75,
  title = {Low-density photodissociation regions},
  author = {Hollenbach, David J. and Tielens, A. G. G. M. and Takahashi, Takamasa},
  year = {1991},
  url = {https://ntrs.nasa.gov/citations/19910062679},
  note = {Source identifier: 19910062679}
}