@book { DasHerzeinerGrfin,
    title = "Das Herz einer Gräfin",
    subtitle = "Roman",
    author = "Günter {Ruch}",
    year = "2019",
    publisher = "dotbooks Verlag",
    address = "München, Deutschland",
    url = "https://www.dotbooks.de/document/460672"
}