@book { FryderykChopin,
    title = "Fryderyk Chopin",
    subtitle = "Sein und Werk - Being and Work",
    author = "Elzbieta {Szczurko} and Tadeusz {Guz}",
    year = "2010",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1107642"
}