@book { IstBildungmessbar,
    title = "Ist Bildung messbar?",
    author = "Robert {Lachner}",
    year = "2007",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638817707",
    url = "https://www.hausarbeiten.de/document/76873"
}