@book { MigrationundMehrsprachigkeit,
    title = "Migration und Mehrsprachigkeit",
    subtitle = "Der Sprachstand türkischer Rückkehrer aus Deutschland",
    author = "Helmut {Daller}",
    year = "1999",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1088322"
}