@book { SozialstaatlichkeitimUmbruch,
    title = "Sozialstaatlichkeit im Umbruch?",
    author = "Stefan {Petzold}",
    year = "2012",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783656317357",
    url = "https://www.hausarbeiten.de/document/205050"
}