@article{DachwaldSeboldtLoebetal.2008,
  author    = {Dachwald, Bernd and Seboldt, Wolfgang and Loeb, H. W. and Schartner, Karl-Heinz},
  title     = {Main Belt Asteroid Sample Return Mission Using Solar Electric Propulsion},
  series = {Acta Astronautica. 63 (2008), H. 1-4},
  journal   = {Acta Astronautica. 63 (2008), H. 1-4},
  isbn      = {0094-5765},
  pages     = {91 -- 101},
  year      = {2008},
  language  = {en}
}
@book{Ley2008,
  author    = {Ley, Wilfried},
  title     = {Handbuch der Raumfahrttechnik / Ley, Wilfried ; Wittmann, Klaus ; Hallmann, Willi [Hrsg.]},
  publisher = {Hanser},
  address   = {M{\"u}nchen},
  isbn      = {978-3-446-41185-2},
  pages     = {814 S. : zahlr. Ill., graph. Darst.},
  year      = {2008},
  language  = {de}
}