↑Charles Previté-Orton, "Italy and Provence, 900–950." in The English Historical Review. 32 (127), p. 347.
↑Constance Bouchard, "Burgundy and Provence, 879-1032." in Timothy Reuter e.a. (ed.), The New Cambridge Medieval History: Volume 3, c. 900 - c.1024. Cambridge, Cambridge University Press, 199, p. 340.
↑ abConstance Bouchard, "Burgundy and Provence, 879-1032," p. 341.
↑Charles Previté-Orton, "Italy and Provence, 900–950," p. 341.