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Gravner, Janko (2003), "Growth phenomena in cellular automata", New Constructions in Cellular Automata, Santa Fe Institute Studies in the Sciences of Complexity, Oxford University Press, pp. 161–182, archived from the original on 2010-06-26
Gravner, Janko (2003), "Growth phenomena in cellular automata", New Constructions in Cellular Automata, Santa Fe Institute Studies in the Sciences of Complexity, Oxford University Press, pp. 161–182, archived from the original on 2010-06-26