@book { DerFaktorAlterbeimFremdsprachenerwerb,
    title = "Der Faktor Alter beim Fremdsprachenerwerb",
    author = "Jenny {Fischer}",
    year = "2012",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783656215509",
    url = "https://www.hausarbeiten.de/document/195770"
}