Cowan, Edward J., "The Invention of Celtic Scotland", n'ediciones de Edward J. Cowan y R. Andrew McDonald, Alba: Celtic Scotland in the Middle Ages, (East Lothian, 2000), páxs. 1–23 Dalton, Paul, "Scottish Influence on Durham, 1066-1214", n'ediciones de David Rollason, Margaret Harvey y Michael Prestwich, Anglu-Norman Durham, 1093-1193, páxs. 339-52