@book { ffentlichkeitohneTradition,
    title = "Öffentlichkeit ohne Tradition",
    subtitle = "Bulgariens Aufbruch in die Moderne",
    author = "Harald {Heppner} and Rumjana {Preshlenova}",
    year = "2003",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1095635"
}