@book { GeheimspracheninMittelundSdosteuropa,
    title = "Geheimsprachen in Mittel- und Südosteuropa",
    author = "Christian {Efing} and Corinna {Leschber}",
    year = "2009",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-00489-2",
    url = "https://www.peterlang.com/document/1054342"
}