@book { VegetarischGesund,
    title = "Vegetarisch. Gesund.",
    author = "Dr. med. Sigrid {Steeb}",
    year = "2015",
    publisher = "Schlütersche Verlagsgesellschaft mbH & Co. KG",
    address = ", Deutschland",
    url = "https://schluetersche.openpublishing.com/document/404003"
}