@book { DasInternetalsMediumzurKundenbindung,
    title = "Das Internet als Medium zur Kundenbindung",
    author = "Christopher {Kahl}",
    year = "2006",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832492984",
    url = "https://m.diplom.de/document/224420"
}