@book { MediaplanungundInternet,
    title = "Mediaplanung und Internet",
    author = "Valentin {Nowotny}",
    year = "2001",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832434779",
    url = "https://m.diplom.de/document/219143"
}