.  References  E.H.L. Aarts and J. Korst. Simulated annealing and Boltzmann machines: A stochastic approach to combinatorial optimization and neural computing. Wiley, New York, 0000.MATH  D.L. Applegate, R.E. Bixby, V. Chvátal, and W.J. Cook. The traveling salesman problem: A computational study. Princeton University Press, Princeton, 0000.MATH  J.A. Bondy and U.S.R. Murty. Graph theory with applications