@book { Kompetenzensichtbarmachen,
    title = "Kompetenzen sichtbar machen",
    subtitle = "Zum Einsatz von Kompetenzportfolios in Waldorfschulen",
    author = "Michael {Brater} and Dieter {Haselbach} and Antonia {Stefer}",
    year = "2010",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1135539"
}