1. C. Babbage, “On the mathematical powers of the calculating engine,” unpublished manuscript, December 1837, Oxford, Buxton Ms7, Museum of History of Science. Printed in “The Origins of Digital Computers: Selected Papers”, B. Randell (ed.), Springer, 1974, pp. 17–52
2. A. Avizionis, J.C. Laprie, “Dependable Computing: from concepts to design diversity,” Proceedings of the IEEE, Vol. 74, No. 5, May 1986, pp. 629–638
3. A. Avizienis, “The N-Version approach to fault-tolerant software,” IEEE Transactions on Software Engineering, Vol. 11, No. 12, December 1985, pp. 1491–1501
4. B. Randell, “System Structure for Software Fault Tolerance,” IEEE Trans. on Software Engineering, Vol. 1, No. 2, June 1975, pp.220–232
5. D. Pradhan, “Fault-tolerant Computer System Design”, Prentice Hall, 1996