@article{WittmannBewersdorffGoerleretal.1993,
  author    = {Wittmann, Klaus and Bewersdorff, A. and G{\"o}rler, G.P. and Otto, G.},
  title     = {Solidification of silver-germanium alloys in an amorphous matrix aboard the space station Mir},
  series = {Acta Astronautica. 29 (1993), H. 7},
  journal   = {Acta Astronautica. 29 (1993), H. 7},
  isbn      = {0094-5765},
  pages     = {547 -- 552},
  year      = {1993},
  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}
}
@article{WittmannPadeken1993,
  author    = {Wittmann, Klaus and Padeken, D.},
  title     = {The User Center for Microgravity MUSC - Support for space experiments},
  series = {DLR-Nachrichten. 70 (1993)},
  journal   = {DLR-Nachrichten. 70 (1993)},
  isbn      = {0937-0420},
  pages     = {19 -- 24},
  year      = {1993},
  language  = {en}
}
@article{WittmannSchmidtPadekenetal.1988,
  author    = {Wittmann, Klaus and Schmidt, H. P. and Padeken, D. and Hildmann, B.},
  title     = {The Microgravity User Support Centre (MUSC)},
  series = {ESA SP. 277 (1988)},
  journal   = {ESA SP. 277 (1988)},
  isbn      = {0379-6566},
  pages     = {525},
  year      = {1988},
  language  = {en}
}
@article{Wittmann1993,
  author    = {Wittmann, Klaus},
  title     = {The microgravity User Support Centre},
  series = {Space Technology - Industrial and Commercial Applications. 13 (1993), H. 2},
  journal   = {Space Technology - Industrial and Commercial Applications. 13 (1993), H. 2},
  isbn      = {0892-9270},
  pages     = {121 -- 124},
  year      = {1993},
  language  = {en}
}
@article{WittmannFortezza1992,
  author    = {Wittmann, Klaus and Fortezza, R.},
  title     = {Telescience opportunities in the precursor flights},
  series = {Space Technology - Industrial and Commercial Applications. 13 (1992), H. 2},
  journal   = {Space Technology - Industrial and Commercial Applications. 13 (1992), H. 2},
  isbn      = {0892-9270},
  pages     = {221 -- 226},
  year      = {1992},
  language  = {en}
}
@book{Ley1999,
  author    = {Ley, Wilfried},
  title     = {Raumflugbetrieb : Gemeinschaftsveranstaltung der FH Aachen, der DGLR und der DLR / 12. Raumfahrt-Kolloquium an der Fachhochschule Aachen, 11. November 1999. / Ley Wilfried [Hrsg.]},
  publisher = {DGLR},
  address   = {Bonn},
  isbn      = {3-932182-07-03},
  pages     = {VIII, 215 S. : zahlr. Ill., graph. Darst.},
  year      = {1999},
  language  = {de}
}
@book{Ley2000,
  author    = {Ley, Wilfried},
  title     = {Meteoriten und Space Debris : Gemeinschaftsveranstaltung der FH Aachen, der DGLR und der DLR / 13. Raumfahrt-Kolloquium an der Fachhochschule Aachen, 23. November 2000. / Ley, Wilfried [Hrsg.]},
  publisher = {DGLR},
  address   = {Bonn},
  isbn      = {3-932182-14-6},
  pages     = {VIII, 296 S. : zahlr. Ill., graph. Darst.},
  year      = {2000},
  language  = {de}
}
@book{GerhardtKramer1982,
  author    = {Gerhardt, Hans Joachim and Kramer, Carl},
  title     = {Untersuchungen zur Lagesicherung von Flachd{\"a}chern mittels Kies- und Plattenabdeckungen},
  publisher = {IRB-Verl.},
  address   = {Stuttgart},
  pages     = {26, [18] S. : Ill., graph. Darst.},
  year      = {1982},
  language  = {de}
}