@book { ZweisprachigkeitundbilingualerUnterricht,
    title = "Zweisprachigkeit und bilingualer Unterricht",
    author = "Magdalena {Olpinska-Szkieko} and Loretta {Bertelle}",
    year = "2014",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-04395-2",
    url = "https://www.peterlang.com/document/1048549"
}