@book { KritikamModellPiagets,
    title = "Kritik am Modell Piagets",
    author = "Marcel {Haldenwang}",
    year = "2002",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638128919",
    url = "https://www.hausarbeiten.de/document/4728"
}