@book { QuovadisDaFII,
    title = "Quo vadis, DaF? II",
    author = "Silke {Gester} and Erika {Kegyes}",
    year = "2014",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-05099-8",
    url = "https://www.peterlang.com/document/1050403"
}