1. Polynomial time approximation schemes for euclidean TSP and other geometric problems;Arora,1996
2. Introduction to Algorithms;Cormen,1990
3. Computers and Intractability: A Guide to the Theory of NP Completeness;Garey,1979
4. Approximation results for kinetic variants of TSP;Hammar,1999
5. Moving target TSP;Helvig,1998