@book { BildungsreforminPreuen,
    title = "Bildungsreform in Preußen",
    author = "Robert {Richter}",
    year = "2006",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638549394",
    url = "https://www.hausarbeiten.de/document/61493"
}