@book { DerBerufdesLehrers,
    title = "Der Beruf des Lehrers",
    author = "Hildegard {Schnell}",
    year = "2007",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638009607",
    url = "https://www.hausarbeiten.de/document/84677"
}