@book { RisikenimEinkauf,
    title = "Risiken im Einkauf",
    author = "Martin {Grotegut}",
    year = "2006",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832494650",
    url = "https://m.diplom.de/document/224596"
}