@book{BuderKadenSchmidtetal.2002,
  author    = {Margret Buder and Klaus Kaden and Almut Schmidt and Cornelia Ziege},
  title     = {Rahmenlehrplan Geografie : Sekundarstufe 1},
  isbn      = {3-89685-838-6},
  year      = {2002},
}