@book { SelbstverantwortlichesLernenanFreienWaldorfschulen,
    title = "Selbstverantwortliches Lernen an Freien Waldorfschulen",
    author = "Michael {Harslem} and Dirk {Randoll}",
    year = "2013",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-03487-5",
    url = "https://www.peterlang.com/document/1047758"
}