@book { Weihnachtenhartzart,
    title = "Weihnachten hart + zart",
    author = "Christoph {Ernst} and Autorengruppe {Blut und Feder}",
    year = "2016",
    publisher = "Bedey Media GmbH",
    address = "Hamburg, Deutschland",
    url = "https://kaderaverlag.openpublishing.com/document/318365"
}