@book { DerHerrderschwarzenFestung,
    title = "Der Herr der schwarzen Festung",
    author = "Jona {Dreyer}",
    year = "2023",
    publisher = "Tschök & Tschök GbR",
    address = ", Deutschland",
    url = "https://tolino.openpublishing.com/document/1368416"
}