@book { DieitalienischeLiteraturdesDuecento,
    title = "Die italienische Literatur des Duecento",
    author = "Heinz Willi {Wittschier}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1089911"
}