Thomas Cahill (2011). “How The Irish Saved Civilization: The Untold Story of Ireland's Heroic Role from the Fall of Rome to the Rise of Medieval Europe”, p.71, Hachette UK
Benjamin Disraeli (Earl of Beaconsfield) (1865). ““Church and Queen.” Five speeches delivered by the Rt. Hon. B. Disraeli, M.P., 1860-1864. Edited, with a preface, by a member of the University of Oxford [i.e. the Hon. Frederick Lygon, afterwards Earl Beauchamp].”, p.72