@book { GustavMahlersKlangwelt,
    title = "Gustav Mahlers Klangwelt",
    subtitle = "Studien zur Instrumentation",
    author = "Altug {Ünlü}",
    year = "2006",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1100749"
}