@book { EinfhrungderElementenachDINENISO9000ff,
    title = "Einführung der Elemente nach DIN EN ISO 9000 ff.",
    author = "Stefan {Thoer}",
    year = "1999",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832413125",
    url = "https://m.diplom.de/document/217222"
}