@book { Existenzgrndung,
    title = "Existenzgründung",
    author = "Katrin {Reichenbächer}",
    year = "2003",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832467098",
    url = "https://m.diplom.de/document/222084"
}