@book { Unsere50erJahre,
    title = "Unsere 50er-Jahre",
    author = "Uli {Zeller}",
    year = "2018",
    publisher = "Schlütersche Verlagsgesellschaft mbH & Co. KG",
    address = ", Deutschland",
    url = "https://schluetersche.openpublishing.com/document/441045"
}