@article{5031,
  author = {A. Kosovichev and J. Christensen-Dalsgaard and W. Däppen and W. Dziembowski and Douglas Gough and M. Thompson},
  title = {Sources of uncertainty in direct seismological measurements of the solar helium abundance},
  year = {1992},
  journal = {Monthly Notices of the Royal Astronomical Society},
  volume = {259},
  pages = {536-558},
  url = {http://articles.adsabs.harvard.edu/full/1992MNRAS.259..536K},
  note = {JILA Pub. 4906},
}