@book { DieValidittderSkalendesGemeinsameneuropischenReferenzrahmensfrSprachen,
    title = "Die Validität der Skalen des Gemeinsamen europäischen Referenzrahmens für Sprachen",
    author = "Katrin {Wisniewski}",
    year = "2014",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-03925-2",
    url = "https://www.peterlang.com/document/1048318"
}