1. Wiedermann, J., van Leeuwen, J.: Rethinking computations. In: Proc. of the 6th AISB Symposium on Computing and Philosophy: The Scandal of Computation — What is Computation?, pp. 6–10 (2013)
2. Wikipedia definition of knowledge (June 2013),
http://en.wikipedia.org/wiki/Knowledge
3. Turing, A.M.: On computable numbers, with an application to the Entscheidungsproblem. Proc. London Math. Soc. 42(2), 230–265 (1936)
4. Turing, A.M.: On computable numbers, with an application to the Entscheidungsproblem: A correction. Proc. London Math. Soc. 43(2), 544–546 (1937)
5. van Leeuwen, J., Wiedermann, J.: The Turing machine paradigm in contemporary computing. In: Mathematics Unlimited - 2001 and Beyond