Tham khảo Công tước xứ Normandie

  1. 1 2 Marjorie Chibnall, The Normans (Blackwell, 2006), pp. 15–16.
  2. 1 2 3 4 David Crouch, The Image of Aristocracy in Britain, 1000–1300 (Taylor and Francis, 1992), pp. 40–41.
  3. David C. Douglas, "The Earliest Norman Counts", The English Historical Review, 61, 240 (1946): 129–56.
  4. Elizabeth van Houts (ed.), The Normans in Europe (Manchester University Press, 2000), p. 41, n. 58.
  5. George Beech, "The Participation of Aquitanians in the Conquest of England 1066–1100", in R. Allen Brown, ed., Anglo-Norman Studies IX: Proceedings of the Battle Conference, 1986 (Boydell Press, 1987), p. 16.
  6. Nick Webber, The Evolution of Norman Identity, 911–1154 (Boydell Press, 2005), p. 178.
  7. David Crouch, The Normans: The History of a Dynasty (Hambledon Continuum, 2002), p. 19.