1. Applegate, D., Bixby, R. E., Chvatal, V., & Cook, W. J. (2001). Concorde—a code for solving traveling salesman problems. URL http://www.math.princeton.edu/tsp/concorde.html .
2. LNCS;P. Balaprakash,2007
3. Balaprakash, P., Birattari, M., Stützle, T., Yuan, Z., & Dorigo, M. (2008). Estimation-based ant colony optimization and local search for the probabilistic traveling salesman problem. IRIDIA Supplementary page. URL http://iridia.ulb.ac.be/supp/IridiaSupp2008-018/ .
4. Balaprakash, P., Birattari, M., Stützle, T., & Dorigo, M. (2009). Adaptive sample size and importance sampling in estimation-based local search for the probabilistic traveling salesman problem. European Journal of Operational Research, 199(1), 98–110.
5. Bentley, J. L. (1992). Fast algorithms for geometric traveling salesman problems. ORSA Journal on Computing, 4(4), 387–411.