1. OED: Computation, n. In: Oxford English Dictionary. September 2009 edn. OUP (2009), http://dictionary.oed.com/cgi/entry/50045985 (January 5, 2010)
2. Llull, R., Bonner, A. (ed. and trans.): Selected Works of Ramon Llull, 1232–1316, 2 volumes. Princeton University Press, Princeton (1985)
3. Gardner, M.: Logic Machines and Diagrams. McGraw-Hill, New York (1958)
4. Lecture Notes in Computer Science;T. Sales,1997
5. Lecture Notes in Computer Science;A. Bonner,1997