@book { UngleichheitinderBildunginDeutschland,
    title = "Ungleichheit in der Bildung in Deutschland",
    author = "Christian {Winkelmann}",
    year = "2012",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783656215837",
    url = "https://www.hausarbeiten.de/document/195434"
}