@book { DieWarnfunktiondesAbschlussprfers,
    title = "Die Warnfunktion des Abschlussprüfers",
    author = "Christian {Heintze}",
    year = "2021",
    publisher = "Meidenbauer",
    address = ", Germany",
    url = "https://www.peterlang.com/document/1105813"
}