@book { DDRForschungvor1989unddanach,
    title = "DDR-Forschung vor 1989 und danach",
    author = "Christian {Schmehl}",
    year = "2014",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    url = "https://m.diplom.de/document/284116"
}