Johnston, A.W. (July 1916) "Orkneyinga Saga". JSTOR/The Scottish Historical Review. Vol. 13, No. 52. p. 393. Retrieved 27 January 2014.
Clouston (1918), p. 15 Clouston, J. Storer (1918), "Two Features of the Orkney Earldom", The Scottish Historical Review, 16 (61), Edinburgh University Press/JSTOR: 15–28, JSTOR25519122
Radner (1978), FA 330 Radner, Joan N., ed. (1978). "Fragmentary Annals of Ireland". CELT: Corpus of Electronic Texts. Translated by Radner, Joan N. University College Cork. Retrieved 10 March 2007.
umanitoba.ca
"Peter St. John" University of Manitoba. Retrieved 1 April 2018.
worldcat.org
search.worldcat.org
Stølen (1988), p. 259 Stølen, Anders (1988). "Frå Jarleætta på Sunnmøre til Blindheim-ætta og Smør-ætta". Norsk Slekthistorisk Tidsskrift (in Norwegian). 31: 259–277. ISSN0029-2141.