@book { BundestagsparteienimUmbruch,
    title = "Bundestagsparteien im Umbruch",
    author = "Lothar {Geisler}",
    year = "2022",
    publisher = "Neue Impulse Verlag",
    address = "Essen, Deutschland",
    url = "https://neueimpulseverlag.openpublishing.com/document/1243733"
}