@book { Muttilsstgren,
    title = "Mutti lässt grüßen...",
    author = "Margarete {Schneberger} and Sonja {Jahn} and Elfriede {Marino}",
    year = "2013",
    publisher = "Schlütersche Verlagsgesellschaft mbH & Co. KG",
    address = ", Deutschland",
    url = "https://schluetersche.openpublishing.com/document/403826"
}