@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{DachwaldSeboldtRichter2006,
  author    = {Dachwald, Bernd and Seboldt, W. and Richter, L.},
  title     = {Multiple rendezvous and sample return missions to near-Earth objects using solar sailcraft / Dachwald, B. ; Seboldt, W. ; Richter, L.},
  series = {Acta Astronautica. 59 (2006), H. 8-11},
  journal   = {Acta Astronautica. 59 (2006), H. 8-11},
  isbn      = {0094-5765},
  pages     = {768 -- 776},
  year      = {2006},
  language  = {en}
}
@article{DachwaldSeboldtRichter2003,
  author    = {Dachwald, Bernd and Seboldt, W. and Richter, L.},
  title     = {Multiple Rendezvous and Sample Return Missions to Near-Earth Asteroids Using Solar Sailcraft},
  series = {Proceedings of the Fifth IAA International Conference on Low Cost Planetary Missions : 24 - 26 September 2003, ESTEC, Noordwijk, the Netherlands / [comp. by R. A. Harris]},
  journal   = {Proceedings of the Fifth IAA International Conference on Low Cost Planetary Missions : 24 - 26 September 2003, ESTEC, Noordwijk, the Netherlands / [comp. by R. A. Harris]},
  publisher = {ESA},
  address   = {Noordwijk},
  isbn      = {92-9092-853-0},
  pages     = {351 -- 358},
  year      = {2003},
  language  = {en}
}