This article presents a closed-loop supply chain (CLSC) network design problem consisting of both forward and reverse material flows. Here, a four-echelon single-product system is introduced in which multiple transportation channels are considered between the nodes of each echelon. Each design...

Solving a multiple travelling salesperson (mTSP) is more difficult than solving a travelling salesperson. Although the TSP has received a great deal of attention, the research on the mTSP is limited. In the mTSP, the N cities must be partitioned into m tours, with each tour resulting in a TSP...