@book { VonLeoninzuPerotin,
    title = "Von Leonin zu Perotin",
    subtitle = "Der musikalische Paradigmenwechsel in Paris um 1210",
    author = "Rudolf {Flotzinger}",
    year = "2007",
    publisher = "Peter Lang Verlag",
    address = "Lausanne, Switzerland",
    url = "https://www.peterlang.com/document/1102413"
}