@conference{9844,
  author = {David Hummer and M. Seaton},
  title = {Interpretation of the spectra of planetary nebulae.},
  year = {1973},
  month = {00/1973},
  url = {http://adsabs.harvard.edu/full/1973MSRSL...5..225H},
  note = {<p>JILA Pub. 907</p>},
}