7Oxford Economics. The Impact of the Express Delivery Industry on the Global Economy[EB/OL].http://wenku.baidu.com/view/7e9dd50852ea551810a6878f.html,2012.
8Shangyao Yan,Chun-Hung Lai,Chia-Hung Chen. A short-term flight scheduling model for international express package delivery[J].{H}JOURNAL OF AIR TRANSPORT MANAGEMENT,2005,(11):368-374.
9Shuguang Liu,Weilai Huang,Huiming Ma.An effective genetic algorithm for the fleet size and mix vehicle routing problems[J].Transportation Research Part E.2008(3)