@book { ControllinginkleinenundmittlerenUnternehmen,
    title = "Controlling in kleinen und mittleren Unternehmen",
    author = "Stefan {Braun}",
    year = "2015",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    url = "https://www.hausarbeiten.de/document/288644"
}