Böckenhauer, Hans-Joachim, Luca Forlizzi, Juraj Hromkovic, Joachim Kneis, Joachim Kupke, Guido Proietti, and Peter Widmayer. “On the Approximability of TSP on Local Modifications of Optimally Solved Instances”. Algorithmic Operations Research 2, no. 2 (September 2, 2007): 83. Accessed October 19, 2019. https://journals.lib.unb.ca/index.php/AOR/article/view/2803.