@book { VirtuelleUnternehmen,
    title = "Virtuelle Unternehmen",
    subtitle = "Analyse einer Organisationsform",
    author = "Christian {Cacha}",
    year = "2002",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832451042",
    url = "https://m.diplom.de/document/220632"
}