(en) Alan Orr Anderson, Early Sources of Scottish History, A.D. 500 to 1286, vol. 2, Londres, Oliver and Boyd, (lire en ligne).
(en) Peter Andreas Munch et Alexander Goss, Chronica Regvm Manniæ et Insvlarvm: The Chronicle of Man and the Sudreys, vol. 1, Douglas, IM, Manx Society, (lire en ligne), p. 100–101.