Bibliografia Normanno-Sveva
Becker Julia
Charters and chancery under Roger I and Roger II
storia
2013
Farnham
Ashgate
Cancelleria, Documenti, Ruggero I, Riggero II, Sicilia
in "Norman Tradition and Transcultural Heritage. Exchange of Cultures in the ‘Norman’ Peripheries of Medieval Europe", a cura di S. Burkhardt - T. Foerster, pp. 79-95