@book { DieDLinie,
    title = "Die D-Linie",
    author = "Frank {Stiefenhofer}",
    year = "2009",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783836632997",
    url = "https://m.diplom.de/document/227050"
}