@book{HentzeMuellerSchlicksupp1990,
  author    = {Hentze, Henner and M{\"u}ller, Klaus-Dieter and Schlicksupp, Helmut},
  title     = {Praxis der Managementtechniken},
  edition   = {1. Auf.},
  publisher = {Hanser},
  address   = {M{\"u}nchen [u.a.]},
  isbn      = {3-446-15046-3},
  pages     = {256 S. : graph. Darst.},
  year      = {1990},
  language  = {de}
}
@book{SteinhausenZoerkendoerfer1990,
  author    = {Steinhausen, Detlef and Z{\"o}rkend{\"o}rfer, Siegfried},
  title     = {Statistische Datenanalyse mit dem Programmsystem SPSS x und SPSS PC +},
  edition   = {2., v{\"o}llig {\"u}berarb.},
  publisher = {Oldenbourg},
  address   = {M{\"u}nchen [u.a.]},
  isbn      = {3-486-21700-3},
  pages     = {VI, 157 S.},
  year      = {1990},
  language  = {de}
}
@book{MulthaupPluemer1990,
  author    = {Multhaup, Roland and Pl{\"u}mer, Thomas},
  title     = {Entsorgungslogistik},
  edition   = {1. Aufl.},
  publisher = {Verl. T{\"U}V Rheinland},
  address   = {K{\"o}ln},
  isbn      = {3-88585-831-2},
  pages     = {206 S. : Ill., graph. Darst.},
  year      = {1990},
  language  = {de}
}