@book { DasInterneKontrollsystemimUnternehmen,
    title = "Das Interne Kontrollsystem im Unternehmen",
    author = "Michael A. {Klinger} and Oskar {Klinger}",
    year = "2011",
    publisher = "Vahlen",
    address = "München, Deutschland",
    url = "https://vahlen.openpublishing.com/document/1220853"
}