@book { DeutschinEstlandundUngarn,
    title = "Deutsch in Estland und Ungarn",
    subtitle = "Beiträge zur Germanistik und Fachdidaktik",
    author = "Winfried {Ulrich}",
    year = "2001",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1092163"
}