@article{WellsteinLanger2001,
  author    = {Wellstein, Stephan and Langer, Norbert},
  title     = {Constraints on the initial mass limit for black hole information from the massive X-ray binary Wray 977},
  isbn      = {3-540-41581-5},
  year      = {2001},
  language  = {en}
}
@article{WellsteinLangerBraun2001,
  author    = {Wellstein, Stephan and Langer, Norbert and Braun, H.},
  title     = {Formation of contact in massive close binaries},
  year      = {2001},
  language  = {en}
}