@book { DieRechtsstellungderBundestagsfraktionen,
    title = "Die Rechtsstellung der Bundestagsfraktionen",
    author = "Berthold {Stevens}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1089594"
}