@book { KundenbindungdurchdasInternet,
    title = "Kundenbindung durch das Internet",
    author = "Christoph {Klaus}",
    year = "2000",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832428938",
    url = "https://m.diplom.de/document/218619"
}