@book { DasGeheimniszweierHerzen,
    title = "Das Geheimnis zweier Herzen",
    author = "Anne {Gracie}",
    year = "2021",
    publisher = "dp DIGITAL PUBLISHERS GmbH",
    address = "Stuttgart, Deutschland",
    url = "https://shop.digitalpublishers.de/document/1129198"
}