John Craig, A New Universal Etymological, Technological, and Pronouncing Dictionary of the English Language Embracing All the Terms Used in Art, Science, and Literature (London, 1844), p. 130 online.
Henry Woldmar Ruoff, The Standard Dictionary of Facts (The Frontier press company, 1916), p. 222 online.
Leslie Ross, Medieval Art: A Topical Dictionary (Greenwood Publishing Group, 1996), p. 205 online.
John Gould, Biographical Dictionary of Eminent Artists: Comprising Painters, Sculptors, Engravers, and Architects, from the Earliest Ages to the Present Time (London: E. Wilson, 1835), p. xc online.
