John Ruskin, Charles Eliot Norton, John Lewis Bradley, Ian Ousby (1987). “The Correspondence of John Ruskin and Charles Eliot Norton”, p.59, Cambridge University Press
John Ruskin (1855). “Notes on Some of the Principal Pictures Exhibited in the Rooms of the Royal Academy, the Old and New Societies of Painters in Water Colours, the Society of British Artists and the French Exhibition”, p.11