@book { ZahlungssystemeimElectronicCommerce,
    title = "Zahlungssysteme im Electronic Commerce",
    author = "Nils {Kück}",
    year = "2000",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832420000",
    url = "https://m.diplom.de/document/217841"
}