@book { ITControlling,
    title = "IT-Controlling",
    author = "Ralf {Kesten} and Arno {Müller} and Hinrich {Schröder}",
    year = "2013",
    publisher = "Vahlen",
    address = "München, Deutschland",
    url = "https://vahlen.openpublishing.com/document/1220821"
}