@article{9525,
  author = {David Hummer and G. Rybicki},
  title = {Radiative transfer in spherically symmetric systems. The conservative grey case},
  year = {1971},
  journal = {Monthly Notices of the Royal Astronomical Society},
  volume = {152},
  chapter = {1},
  pages = {1-19},
  month = {00/1971},
  url = {http://adsabs.harvard.edu/full/1971MNRAS.152....1H},
  doi = {10.1093/mnras/152.1.1},
  note = {JILA Pub. 721},
}