@article{9477,
  author = {David Hummer and G. Rybicki},
  title = {The Formation of Spectral Lines},
  year = {1971},
  journal = {Annual Review of Astronomy and Astrophysics},
  volume = {9},
  pages = {237-270},
  month = {Jan-09-1971},
  issn = {0066-4146},
  doi = {10.1146/annurev.aa.09.090171.001321},
}