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Krippendorff, Klaus. "Combinatorial Explosion". Web Dictionary of Cybernetics and Systems. PRINCIPIA CYBERNETICA WEB. Archived from the original on 6 August 2010. Retrieved 29 November 2010.
web.archive.org
Krippendorff, Klaus. "Combinatorial Explosion". Web Dictionary of Cybernetics and Systems. PRINCIPIA CYBERNETICA WEB. Archived from the original on 6 August 2010. Retrieved 29 November 2010.