Mathilde dari Boulogne (1170–1210)Sumber
- The Lais of Marie de France. Diterjemahkan oleh Burgess, Glyn S.; Busby, Keith. Penguin. 1986.
- Pollock, M.A. (2015). Scotland, England and France after the Loss of Normandy, 1204-1296. The Boydell Press.
- McDougall, Sara (2017). Royal Bastards: The Birth of Illegitimacy, 800-1230. Oxford University Press.