@article{8428,
  author = {S. Kawaler and D. Winget and Carl Hansen and I. Iben},
  title = {The helium shell game - Nonradial g-mode instabilities in hydrogen-deficient planetary nebula nuclei},
  year = {1986},
  journal = {The Astrophysical Journal},
  volume = {306},
  pages = {L41},
  month = {Jan-07-1986},
  issn = {0004-637X},
  url = {http://articles.adsabs.harvard.edu/full/1986ApJ...306L..41K},
  doi = {10.1086/184701},
}