@book { DasEndederDDR,
    title = "Das Ende der DDR",
    subtitle = "Eine politische Autopsie",
    author = "Peter {Schwarz} and  {Bund Sozialistischer Arbeiter}",
    year = "2020",
    publisher = "MEHRING Verlag",
    address = "Essen, Deutschland",
    url = "https://mehring.openpublishing.com/document/917215"
}