@book { eCRMGestaltungvonKundenbeziehungenineBusiness,
    title = "eCRM-Gestaltung von Kundenbeziehungen in eBusiness",
    author = "Matthias {Klang}",
    year = "2002",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832449216",
    url = "https://m.diplom.de/document/220488"
}