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2. Genetic and Cultural Evolution of Cooperation, edited by P. Hammerstein (MIT, Cambridge, MA, 2003)
3. K. Sigmund, Games of Life (Oxford University Press, Oxford, 1993)
4. R. Axelrod, The Evolution of Cooperation (Basic books, New York, 1984)
5. J. von Neumann, O. Morgenstern, Theory of Games and Economic Behaviour (Princeton University Press, Princeton, 1944)