@book { DasGeheimnisvonBartonHall,
    title = "Das Geheimnis von Barton Hall",
    author = "L.C. {Frey}",
    year = "2016",
    publisher = "via tolino media",
    address = "München, Deutschland",
    url = "https://tolino.openpublishing.com/document/1021393"
}