@book { IchhelfemirselbstVerdauungsundDarmbeschwerden,
    title = "Ich helfe mir selbst - Verdauungs- und Darmbeschwerden",
    author = "Dr. Andrea {Flemmer}",
    year = "2021",
    publisher = "humboldt",
    address = "Hannover, Deutschland",
    url = "https://schluetersche.openpublishing.com/document/993663"
}