↑ Summerson, Sir John (1948). Heavenly Mansions and Other essays on Architecture. London: Cresset Press.
↑ Eugène-Emmanuel Viollet-le-Duc. ([1854] 1990). The foundations of architecture. New York: George Braziller. P. 195. (Translated by Kenneth D. Whitehead from the original French.)
↑ John Ruskin. ([1880] 1989). The seven lamps of architecture. New York: Dover Publications. P. 194
↑ Summerson, Sir John (1948). Heavenly Mansions and Other essays on Architecture. London: Cresset Press.
