^Parry, Kenneth (1996). Depicting the Word: Byzantine Iconophile Thought of the Eighth and Ninth Centuries. Leiden and New York: Brill. pp 11-15. ISBN90-04-10502-6.
^A. A. Vasiliev, History of the Byzantine Empire: 324–1453, p. 564.
^A.A. Vasiliev, History of the Byzantine Empire, p. 566.