@article{WittmannUlamecRichter1999,
  author    = {Wittmann, Klaus and Ulamec, S and Richter, L},
  title     = {Lander Systems for Planetary Missions},
  series = {Laboratory astrophysics and space research / ed. by P. Ehrenfreund},
  journal   = {Laboratory astrophysics and space research / ed. by P. Ehrenfreund},
  publisher = {Kluwer},
  address   = {Dordrecht [u.a.]},
  isbn      = {0-7923-5338-2},
  pages     = {597 -- 621},
  year      = {1999},
  language  = {en}
}
@article{WittmannUlamecFeuerbacheretal.1995,
  author    = {Wittmann, Klaus and Ulamec, S. and Feuerbacher, B. and Rosenbauer, H.},
  title     = {Technical Challenge, Scientific Thrill: A Long Term Lander on an Active Comet},
  series = {Lunar and Planetary Science. 26 (1995)},
  journal   = {Lunar and Planetary Science. 26 (1995)},
  isbn      = {0270-9511},
  pages     = {1431 -- 1432},
  year      = {1995},
  language  = {en}
}
@article{WittmannUlamecFeuerbacheretal.1997,
  author    = {Wittmann, Klaus and Ulamec, S. and Feuerbacher, B. and Rosenbauer, H. (u.a.)},
  title     = {Rosetta Lander - In Situ Investigation of a Cometary Nucleus},
  series = {Lunar and Planetary Science. 28 (1997)},
  journal   = {Lunar and Planetary Science. 28 (1997)},
  isbn      = {0270-9511},
  pages     = {1461 -- 1462},
  year      = {1997},
  language  = {en}
}