10. Bektas, T. (2006). “The multiple traveling salesman problem: an overview of formulations and solution procedures”, Omega, Vol. 34, No. 3, PP. 209–219.
11. Theys, C., Broysy, O., Dullaert, W., Raa. (2010). “Using a TSP heuristic for routing order pickers in warehouses”, European Journal of Operational Research, PP. 755–763.
12. Norouzi, N., et al. (2015). “New mathematical modeling for a facilities location and vehicle routing problem solving by a hybrid imperialist competitive algorithm”, Journal of Industrial Engineering, vol 49, No 1 , PP. 129–137.
13. Parragh, S., Doerner, K. and Hart, R. (2008). “A survey on pickup and delivery problems: Part I, Transportation between customers and depot”, Journal für Betriebswirtschaft, Vol. 58, No. 1, PP. 21–51.
14. Pandelis, D.G., Karamatsoukis, C. and Kyriakidis, G. (2013). “Single vehicle routing problems with a predefined customer order, unified load and stochastic discrete demands”, Probability in the Engineering and Informational Sciences, Vol. 27. No. 1, PP. 1–23.
15. Setak, M., Jalili Bolhassani, S., Karimi, H. and Gorbani, B. (2014). “A node-based mathematical model towards the location routing problem with intermediate replenishment facilities under capacity constraint”, International Journal of Engineering, Vol. 27, No. 6, PP. 911–20.
16. Davoodi, M., Abedin, M., Banyassady, B., Khanteimouri, P. and Mohades A. (2013). “An optimal algorithm for two robots path planning problem on the grid”, Robotics and Autonomous Systems, Vol. 61, No. 12, PP. 1406–1414.
17. Roozbehani, H. and D’Andrea R. (2011). “Adaptive highways on a grid”, In Pradalier, C., Siegwart, R., and Hirzinger, G. (Eds.), Robotics Research, Vol. 70. Springer Berlin/Heidelberg, PP. 661–680.
18. Yu, J. and LaValle, S.M. (2013). “Planning optimal paths for multiple robots on graphs”, Proc. IEEE Int. Conf. on Robotics and Automation (ICRA), May 2013, Kalsruhe, Germany, PP. 3612-3617.
19. Surynek, P. (2010). “An optimization variant of multi-robot path planning is intractable”, Proc. of the 24thAAAI Conference on Artificial Intelligence, PP. 1261–1263.
20. Bruno, J., Coffmann, E. and Sethi, R. (1974). “Scheduling independent tasks to reduce mean finishing time”, Communications of ACM, Vol. 17, No. 7, PP. 382–387.