@article{GrassmannKlunterMirwaldetal.1995,
  author    = {Grassmann, Marianne and Klunter, Martina and Mirwald, Elke and Veith, Ute},
  title     = {Was k{\"o}nnen Schulanf{\"a}nger bereits vor ihrer ersten Mathematikstunde?},
  year      = {1995},
  language  = {de}
}
@article{GrassmannKlunterMirwaldetal.1995,
  author    = {Grassmann, Marianne and Klunter, Martina and Mirwald, Elke and Veith, Ute},
  title     = {Arithmetische Kompetenzen von Schulanf{\"a}ngern-Schlußfolgerungen f{\"u}r die Gestaltung des Anfangsunterrichts},
  year      = {1995},
  language  = {de}
}
@article{GrassmannKlunterMirwaldetal.1998,
  author    = {Grassmann, Marianne and Klunter, Martina and Mirwald, Elke and Veith, Ute},
  title     = {Untersuchungen {\"u}ber Vorkenntnisse und Informelle L{\"o}sungsstrategien zu zentralen Inhalten des Mathematikunterrichts der Klasse 3},
  issn      = {0949-6785},
  year      = {1998},
  language  = {de}
}
@article{GrassmannMirwaldKlunteretal.2000,
  author    = {Grassmann, Marianne and Mirwald, Elke and Klunter, Martina and Veith, Ute},
  title     = {Untersuchungen {\"u}ber Vorkenntnisse von Schulkindern zu zentralen Inhalten des Mathematikunterrichts der Klasse 4, Teil 2},
  year      = {2000},
  language  = {de}
}
@article{GrassmannMirwaldKlunteretal.2000,
  author    = {Grassmann, Marianne and Mirwald, Elke and Klunter, Martina and Veith, Ute},
  title     = {Untersuchungen {\"u}ber Vorkenntnisse von Schulkindern zu zentralen Inhalten des Mathematikunterrichts der Klasse 4, Teil 1},
  year      = {2000},
  language  = {de}
}