@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{WittmannFeuerbacherUlamecetal.1999,
  author    = {Wittmann, Klaus and Feuerbacher, B. and Ulamec, S. and Rosenbauer, H. (u.a.)},
  title     = {Rosetta Lander - In Situ Characterisation of a Comet Nucleus},
  series = {Acta Astronautica. 45 (1999), H. 4-9},
  journal   = {Acta Astronautica. 45 (1999), H. 4-9},
  isbn      = {0094-5765},
  pages     = {389 -- 395},
  year      = {1999},
  language  = {en}
}