@book { LeonardounddasRtseldesAlchimisten,
    title = "Leonardo und das Rätsel des Alchimisten",
    author = "Alfred {Bekker}",
    year = "2018",
    publisher = "Uksak E-Books",
    address = "Lengerich, Deutschland",
    url = "https://uksakebooks.grin.com/document/418430"
}