@book { Erwachsenenlernen,
    title = "Erwachsenenlernen",
    author = "Carsten {Weerth}",
    year = "2012",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783656171102",
    url = "https://www.hausarbeiten.de/document/191503"
}