Reference
Haxhimusa, Y., Kropatsch, W., Pizlo, Z., & Ion, A. (2007). Approximating TSP Solution by MST based Graph Pyramid. In Proceedings of the 15th International Workshop on Graph-based Representation for Pattern Recognition (pp. 295–306). Springer Lecture Notes in Computer Science. http://hdl.handle.net/20.500.12708/51963