@book { VirtuelleUnternehmen,
    title = "Virtuelle Unternehmen",
    author = "Marc S. {Tenbieg}",
    year = "1998",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832411688",
    url = "https://m.diplom.de/document/217091"
}