@book { RamonLlull,
    title = "Ramon Llull",
    subtitle = "ou ...les premiers jalons d'une Europe tolérante",
    author = "Gabriel {Fragnière}",
    year = "1999",
    publisher = "Peter Lang Verlag",
    address = "Bruxelles, Belgium",
    url = "https://www.peterlang.com/document/1087747"
}