1. Alberti. 1955.Battista Leone, ten Books of Architecture, Edited by: Leoni, James. 150London: Alec Tiranti.
2. Vitruvius. 1960.The Ten Books of Architecture, Edited by: Morgan, M. H. 205–206. New York: Dover.
3. Buttner, O. and Hampe, E. 1976.Bauwerk, Tragwerk, Tragstruktur, 159Berlin, (GDR): VEB Verlag fur Bauwesen.
4. Ware, S. and Heyman, J. 1972.Coulomb's Memoir on Statics, 75–6. London: Cambridge University Press. Quoted from a translation by
5. 76Ibid.