1. The vehicle routing problem;Toth,2001
2. US Department of Labor, Occupational Outlook Handbook, Bureau of Labor Statistics, 2010–11.
3. The Travelling Salesman Problem,1985
4. The truck dispatching problem;Dantzig;Management Science,1959
5. Reducibility among combinatorial problems;Karp;Complexity of Computer Computations, Advances in Computing Research,1972