1. M.R. Garey, D.S. Johnson, Computers and Intractability: A Guide to the Theory of NP-Completeness (W. H. Freeman & Co., New York, NY, USA, 1979).
2. E.A. Feigenbaum, J. Feldman, Computers and Thought (AAAI Press, 1963).
3. M.H.J. Romanycia, F.J. Pelletier, Computational Intelligence 1(1), 47 (1985).
4. F.W. Glover, Comput. Oper. Res. 13, 533 (1986).
5. J.R. Koza, in IJCAI (1989), pp. 768–774.