@book { EcommerceausVerbrauchersicht,
    title = "E-commerce aus Verbrauchersicht",
    author = "Sandra {Gröll}",
    year = "2001",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832431679",
    url = "https://m.diplom.de/document/218863"
}