@misc{indiciae2f273beb8968,
  title = {The Sobolev approximation for line formation with partial frequency redistribution},
  author = {Hummer, D. G. and Rybicki, G. B.},
  year = {1992},
  url = {https://ntrs.nasa.gov/citations/19920044547},
  note = {Source identifier: 19920044547}
}