@book { Unternehmensgrndung,
    title = "Unternehmensgründung",
    subtitle = "Begleiten statt Beraten",
    author = "Jürgen {Bauer}",
    year = "1999",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832419523",
    url = "https://m.diplom.de/document/217796"
}