@book{MoellerHaneltHolubeketal.2005,
  author    = {M{\"o}ller, Angelika and Hanelt, Martina and Holubek, Ines and Schmidt, Ramona and Schmidt, Sabine and Schultheiß, Irina and Stamm, Reinhard},
  title     = {Mathematik : Lehrbuch f{\"u}r die Klasse 6 ; Berlin / Brandenburg},
  publisher = {DUDEN PAETEC},
  address   = {Berlin},
  isbn      = {3-89818-222-3},
  pages     = {224 S.},
  year      = {2005},
  language  = {de}
}
@book{HaneltHolubekMoelleretal.2005,
  author    = {Hanelt, Martina and Holubek, Ines and M{\"o}ller, Angelika and Schmidt, Ramona and Schultheiß, Irina and Stamm, Reinhard},
  title     = {Duden Mathematik : Ausg. G, Gymnasium ; Klasse 6},
  series = {Duden, Mathematik},
  journal   = {Duden, Mathematik},
  publisher = {DUDEN PAETEC},
  address   = {Berlin},
  isbn      = {3-89818-573-7},
  pages     = {224 S.},
  year      = {2005},
  language  = {de}
}