@book { bungeninBetriebswirtschaftslehre,
    title = "Übungen in Betriebswirtschaftslehre",
    author = "Michael {Bitz} and Jürgen {Ewert}",
    year = "2014",
    publisher = "Vahlen",
    address = "München, Deutschland",
    url = "https://vahlen.openpublishing.com/document/1220916"
}