@book { CustomerSelfCareServicesimInternet,
    title = "Customer Self Care Services im Internet",
    author = "Simone {Fritz}",
    year = "2005",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832490348",
    url = "https://m.diplom.de/document/224193"
}