1. Mark, R., “Gothic Cathedrals and Structural Rationalism,”Trans. of the NY Acad. of Sci., Ser. 11,33 (6),607–624 (June 1971).
2. Abraham, P., Viollet-le-Duc et le Rationalisme Médiéval, Vincent, Freal & Co., Paris (1934).
3. Panofsky, E., Gothic Architecture and Scholasticism, The World Publishing Co., New York, 53–59 (1957).
4. Branner, R., “Gothic Architecture 1160–1180 and its Romanesque Sources,”Acts of the 20th Intl. Cong. on the History of Art, New York,1,92–104 (1961).
5. Mark, R., “Structural Analysis of Gothic Cathedrals: a comparison of Chartres and Bourges,”Scientific American,227 (5),90–99 (Nov. 1972).