@book { WerbungundKonjunktur,
    title = "Werbung und Konjunktur",
    author = "Clemens {Roer}",
    year = "1998",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832410247",
    url = "https://m.diplom.de/document/216918"
}