@book { FallstudienzurUnternehmensfhrung,
    title = "Fallstudien zur Unternehmensführung",
    author = "Ralf {Dillerup} and Roman {Stoi}",
    year = "2012",
    publisher = "Vahlen",
    address = "München, Deutschland",
    url = "https://vahlen.openpublishing.com/document/1220880"
}