@book { GrundrissVerfassungsrecht,
    title = "Grundriss Verfassungsrecht",
    author = "Herbert {Bethge} and Gerd Christian von {Coelln}",
    year = "2012",
    publisher = "Vahlen",
    address = "München, Deutschland",
    url = "https://vahlen.openpublishing.com/document/1220773"
}