@book { MarketingimInternet,
    title = "Marketing im Internet",
    author = "Jörg {Hauck}",
    year = "1998",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832408299",
    url = "https://m.diplom.de/document/216733"
}