@book { KundenbindungimInternet,
    title = "Kundenbindung im Internet",
    author = "Julius {Grote}",
    year = "2002",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832454944",
    url = "https://m.diplom.de/document/220804"
}