@book { DieRevisioneinesQualittsmanagementSystemsnachDIN90002000,
    title = "Die Revision eines Qualitätsmanagement-Systems nach DIN 9000:2000",
    author = "Ulrich {Sellig}",
    year = "2001",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832446864",
    url = "https://m.diplom.de/document/220291"
}