@book { DieHartzReformenausdemBlickwinkelderSystemtheorie,
    title = "Die Hartz-Reformen aus dem Blickwinkel der Systemtheorie",
    author = "Vera {Hillemann}",
    year = "2008",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783836616898",
    url = "https://m.diplom.de/document/226009"
}