1. Arora, S., Barak, B.: Computational Complexity: A Modern Approach. Cambridge University Press, Cambridge (2009)
2. Boone, W.W.: The word problem. Proc. Natl. Acad. Sci. USA 44, 1061–1065 (1958)
3. Braverman, M., Cook, S.: Computing over the reals: foundations for scientific computing. Not. Am. Math. Soc. 53(3), 318–329 (2006)
4. Barry Cooper, S.: Computability Theory. Chapman & Hall/CRC, Boca Raton (2004)
5. Cutland, N.: Computability: An Introduction to Recursive Function Theory. Cambridge University Press, Cambridge (1980)