@book { DieEntwicklungvomBerlinerModellzumHamburgerModell,
    title = "Die Entwicklung vom Berliner Modell zum Hamburger Modell",
    author = "Stefan {Voßen}",
    year = "2011",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783640838318",
    url = "https://www.hausarbeiten.de/document/167419"
}