@article{9058,
  author = {J. Puls and David Hummer},
  title = {The Sobolev approximation for the line force and line source function in a spherically-symmetrical stellar wind with continuum opacity},
  year = {1988},
  journal = {Astronomy and Astrophysics},
  volume = {191},
  pages = {87-98},
  month = {02/1988},
  url = {http://adsabs.harvard.edu/full/1988A\%26A...191...87P},
  note = {JILA Pub. 3560},
}