@book { WerbungimInternet,
    title = "Werbung im Internet",
    author = "Dietmar {Plank}",
    year = "1997",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832404567",
    url = "https://m.diplom.de/document/216422"
}