@article{9468,
  author = {B. Paczynski},
  title = {Evolution of Single Stars. VI. Model Nuclei of Planetary Nebulae},
  year = {1971},
  journal = {Acta Astronomica},
  volume = {21},
  chapter = {417},
  pages = {417-435},
  url = {http://articles.adsabs.harvard.edu/full/1971AcA....21..417P},
  note = {JILA Pub. 832},
}