@book { Controlling,
    title = "Controlling",
    subtitle = "Balanced Scorecard, Kennzahlen, Prozess- und Risikomanagement",
    author = "Dirk {Fischer}",
    year = "2011",
    publisher = "Vahlen",
    address = "München, Deutschland",
    url = "https://vahlen.openpublishing.com/document/1220854"
}