Timothy Bolton, The Empire of Cnut the Great: Conquest and the Consolidation of Power in Northern Europe in the Early Eleventh Century, Northern world 40, Leiden/Boston: Brill, 2009, ISBN9789047443308, p. 263.
Ólafs saga Helga, trans. Hollander, ch. 228, p. 515.
Claus Krag, "The Early Unification of Norway", in The Cambridge History of Scandinavia, ed. Knut Helle, Volume 1 Prehistory to 1520, Cambridge: Cambridge University, 2003, ISBN9780521472999, pp. 184–201, p. 195.
Magnúss saga ins Góða, trans. Hollander, ch. 14, p. 551.
Frank MacLynn, 1066: The Year of the Three Battles, 1998, repr. London: Pimlico, 1999, ISBN9780712666725, p. 107.