@book { SprachbuchundMathematikbuchimVergleich,
    title = "Sprachbuch und Mathematikbuch im Vergleich",
    author = "Christoph {Müller}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1099821"
}