@book { ZahlungsmglichkeitenimInternet,
    title = "Zahlungsmöglichkeiten im Internet",
    author = "René {Schaible}",
    year = "2003",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832473808",
    url = "https://m.diplom.de/document/222669"
}