@article{GiestHartingerKahlert2008,
  author    = {Giest, Hartmut and Hartinger, Andreas and Kahlert, Joachim},
  title     = {Auf dem Weg zu einem Kompetenzmodell f{\"u}r den Sachunterricht : eine vergleichende Zusammenschau},
  year      = {2008},
  language  = {de}
}
@article{GiestHartingerKahlert2008,
  author    = {Giest, Hartmut and Hartinger, Andreas and Kahlert, Joachim},
  title     = {Kompetenzniveaus im Sachunterricht},
  year      = {2008},
  language  = {de}
}
@article{HartingerGiestKahlert2008,
  author    = {Hartinger, Andreas and Giest, Hartmut and Kahlert, Joachim},
  title     = {Kompetenzniveaus im Sachunterricht : eine Einf{\"u}hrung in den Forschungsband},
  year      = {2008},
  language  = {de}
}
@article{KahlertCechGiestetal.2004,
  author    = {Kahlert, Joachim and Cech, Diethard and Giest, Hartmut and Hempel, Marlies and Wittkowske, Steffen and Hartinger, Andreas},
  title     = {Sachunterricht nach PISA und IGLU},
  isbn      = {3-7065-4020- 7},
  year      = {2004},
  language  = {de}
}