@article{LangerHegerBraun1998,
  author    = {Langer, Norbert and Heger, Alexander and Braun, H.},
  title     = {Nucleosynthesis in massive stars},
  year      = {1998},
  language  = {en}
}
@article{LangerBraunWellstein1998,
  author    = {Langer, Norbert and Braun, H. and Wellstein, Stephan},
  title     = {Massive close binaries as source of galatic 26Al},
  year      = {1998},
  language  = {en}
}