John Ruskin (1899). “On the Old Road: A Collection of Miscellaneous Essays and Articles on Art and Literature (Complete)”, p.170, Library of Alexandria
John Ruskin (1854). “On the nature of Gothic architecture: and herein of the true functions of the workman in art. Being the greater part of the 6th chapter of the 2nd vol. of 'Stones of Venice'. [48 p.].”, p.13