@book { DieEntwicklungdesSchulwesensimMittelalter,
    title = "Die Entwicklung des Schulwesens im Mittelalter",
    author = "Sina {Jung}",
    year = "2015",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    url = "https://www.hausarbeiten.de/document/292730"
}