@book { DieimaginreGattung,
    title = "Die imaginäre Gattung",
    subtitle = "Über das musiktheatralische Werk G. Ligetis",
    author = "Maria {Kostakeva}",
    year = "1996",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1083480"
}