C. Baiocchi, Three Small Universal Turing Machines, Proc. 3rd International Conference on Machines, Computations, pp.1-10, 2001.
DOI : 10.1007/3-540-45132-3_1

A. H. Brady, The determination of the value of Rado's noncomputable function ? for four-state Turing machines, Mathematics of Computation, vol.40, issue.162, pp.647-665, 1983.

A. Church, An Unsolvable Problem of Elementary Number Theory, American Journal of Mathematics, vol.58, issue.2, pp.345-363, 1936.
DOI : 10.2307/2371045

J. Cocke and M. Minsky, Universality of Tag Systems with P = 2, Journal of the ACM, vol.11, issue.1, pp.15-20, 1963.
DOI : 10.1145/321203.321206

M. Cook, Universality in elementary cellular automata, Complex Systems, vol.15, issue.1, pp.1-40, 2004.

M. Davis and T. Undecidable, Why G??del didn't have church's thesis, Dover publications, pp.3-24, 1965.
DOI : 10.1016/S0019-9958(82)91226-8

E. L. Post, His life and work, p.xi?xviii, 1994.

M. Liesbeth-de, Closing the circle: An analysis of Emil Post's early work, The Bulletin of Symbolic Logic, vol.12, issue.2, pp.267-289, 2006.

B. Hayes, Theory and Practice, pp.21-28, 1986.
DOI : 10.5149/9780807887813_hayes.15

M. Kudlek and Y. Rogozhin, New Small Universal Circular Post Machines, Fundamentals of Computation Theory : 13th International Symposium, LNCS, vol.2138, pp.217-226, 2001.

S. Lin and T. Rádo, Computer Studies of Turing Machine Problems, Journal of the ACM, vol.12, issue.2, pp.196-212, 1965.
DOI : 10.1145/321264.321270

M. Margenstern, Frontier between decidability and undecidability: a survey, Theoretical Computer Science, vol.231, issue.2, pp.217-251, 2000.
DOI : 10.1016/S0304-3975(99)00102-4

G. Marsaglia, The Marsaglia random number CD-rom, with the Diehard battery of tests of randomness, Department of statistics and supercomputer computations research institute, 1996.

S. J. Maslov and E. L. On, Post's 'Tag' problem, pp.5-56, 1964.

P. Michel, Small Turing machines and generalized busy beaver competition, Theoretical Computer Science, vol.326, issue.1-3, pp.45-56, 2004.
DOI : 10.1016/j.tcs.2004.05.008

M. Minsky, Recursive Unsolvability of Post's Problem of "Tag" and other Topics in Theory of Turing Machines, The Annals of Mathematics, vol.74, issue.3, pp.437-455, 1961.
DOI : 10.2307/1970290

T. Neary and D. Woods, Four Small Universal Turing Machines, Machines, Computations, and Universality. Fifth International Conference, pp.242-254, 2007.
DOI : 10.1007/978-3-540-74593-8_21

D. Pager, The Categorization of Tag Systems in Terms of Decidability, Journal of the London Mathematical Society, vol.2, issue.Part_3, pp.473-480, 1970.
DOI : 10.1112/jlms/2.Part_3.473

H. Peitgen, Hartmut Jürgens, and Dietmar Saupe, Chaos and fractals. New frontiers of science, 1992.

L. Emil and . Post, Formal reductions of the general combinatorial decision problem, American Journal of Mathematics, vol.65, issue.2, pp.197-215, 1943.

C. E. Shannon, A Mathematical Theory of Communication, Bell System Technical Journal, vol.27, issue.3, pp.379-423, 1948.
DOI : 10.1002/j.1538-7305.1948.tb01338.x

J. B. Shearer, Periods of strings (letter to the editor), American Scientist, vol.86, p.207, 1996.

J. Stillwell, Emil Post and His Anticipation of G??del and Turing, Mathematics Magazine, vol.77, issue.1, pp.3-14, 2004.
DOI : 10.2307/3219226

K. Sutner, Cellular automata and intermediate degrees, Theoretical Computer Science, vol.296, issue.2, pp.365-375, 2003.
DOI : 10.1016/S0304-3975(02)00661-8

A. M. Turing, On computable numbers with an application to the Entscheidungsproblem A correction to the paper was published in the same journal, Proceedings of the London Mathematical Society, pp.230-265, 1936.

. John-von-neumann, The general and logical theory of automata, 1966.

H. Wang, Tag systems and lag systems, Mathematische Annalen, vol.4, issue.1, pp.65-74, 1963.
DOI : 10.1007/BF01343730

S. Watanabe, 5-Symbol 8-State and 5-Symbol 6-State Universal Turing Machines, Journal of the ACM, vol.8, issue.4, pp.476-483, 1961.
DOI : 10.1145/321088.321090

S. Wolfram, Cellular automata and complexity. Collected papers, 1994.

D. Woods and T. Neary, On the time complexity of 2-tag systems and small universal Turing machines, 2006 47th Annual IEEE Symposium on Foundations of Computer Science (FOCS'06), pp.439-448, 2006.
DOI : 10.1109/FOCS.2006.58