@book { HandbuchderPersonalberatung,
    title = "Handbuch der Personalberatung",
    author = "Michael {Heidelberger} and Lothar {Kornherr}",
    year = "2014",
    publisher = "Vahlen",
    address = "München, Deutschland",
    url = "https://vahlen.openpublishing.com/document/1220900"
}