@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}
}
@article{WittmannGillessenOttoetal.1996,
  author    = {Wittmann, Klaus and Gillessen, F. and Otto, G. and R{\"o}stel, R.},
  title     = {Undercooling and solidification of metallic melts suspended in a non-nucleating matrix: Experiment NUCAL of the German Spacelab Mission D-2},
  series = {Acta Astronautica. 38 (1996), H. 1},
  journal   = {Acta Astronautica. 38 (1996), H. 1},
  isbn      = {0094-5765},
  pages     = {63 -- 68},
  year      = {1996},
  language  = {en}
}
@article{Wittmann2000,
  author    = {Wittmann, Klaus},
  title     = {Overview of Space Operations at DLR},
  year      = {2000},
  language  = {en}
}
@article{WittmannKehrWillnecker2000,
  author    = {Wittmann, Klaus and Kehr, J. and Willnecker, R.},
  title     = {Decentralized Payload Operations Concept for Columbus},
  year      = {2000},
  language  = {en}
}
@article{WittmannBibringRosenbaueretal.2007,
  author    = {Wittmann, Klaus and Bibring, J.-P. and Rosenbauer, H. and Boehnhardt, H.},
  title     = {The Rosetta Lander ("Philae") Investigations / Bibring, J.-P. ; Rosenbauer, H. ; Boehnhardt, H. ; [...] Wittmann, K.},
  series = {Space Science Reviews. 128 (2007), H. 1-4},
  journal   = {Space Science Reviews. 128 (2007), H. 1-4},
  isbn      = {0038-6308},
  pages     = {205 -- 220},
  year      = {2007},
  language  = {en}
}
@book{LeyWittmannHallmann2009,
  author    = {Ley, Wilfried and Wittmann, Klaus and Hallmann, Willi},
  title     = {Handbook of space technology},
  publisher = {Wiley},
  address   = {Chichester},
  isbn      = {978-0-470-69739-9},
  pages     = {XIII, 882 S. : Ill., graph. Darst.},
  year      = {2009},
  language  = {en}
}