@book { DifferenzierungimUnterricht,
    title = "Differenzierung im Unterricht",
    author = "Matthias {Altmannsberger}",
    year = "2002",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638154499",
    url = "https://www.hausarbeiten.de/document/8494"
}