1. Tang JQ Wang CG and Zuo DJ. (2013). "Optimization model and algorithm of regional transportation structure." Mathematics in practice and theory 13 85-91.
2. Fan YJ. (2009). "Economic mechanism of transport system structure optimization research." Xi'an: Chang'an University.
3. Hao J. (2008). "Research on Optimization of transportation structure of regional transportation." Xi'an: Chang'an University.