@book { AstridsschmutzigesGeheimnis,
    title = "Astrids schmutziges Geheimnis",
    author = "Claudia {Kellner}",
    year = "2024",
    publisher = "via tolino media",
    address = "München, Deutschland",
    url = "https://tolino.openpublishing.com/document/1442622"
}