@book { DasverloreneHerzvonBelfort,
    title = "Das verlorene Herz von Belfort",
    author = "Angelika {Monkberg}",
    year = "2021",
    publisher = "dp DIGITAL PUBLISHERS GmbH",
    address = "Stuttgart, Germany",
    url = "https://shop.digitalpublishers.de/document/1007168"
}