@book { DiedeutscheBalladeim20Jahrhundert,
    title = "Die deutsche Ballade im 20. Jahrhundert",
    author = "Srdan {Bogosavljevic} and Winfried {Woesler}",
    year = "2009",
    publisher = "Peter Lang Verlag",
    address = "Lausanne, Switzerland",
    url = "https://www.peterlang.com/document/1105896"
}