[ 21]  Zhao，Q.，S.Wang，K.Lai, and GXia.A vehicle routing problem with multiple use of vehicles[J]. Advanced Modeling and Optimization, 2002，4(3):21 -40.

[22]  Olivera, A.and Viera, O.Adaptive Memory Programming for the Vehicle Routing Problemwith Multiple Trips[J].Computers and Operations Research,2007，34:28-47.

[23]Romer PM.the Origins of Endogenous Growth[J].Journal ofEconomic Perspective1994,  Vo1.8:3-22.

[24]史秀苹等.城市物流评价指标体系初探[[J].冶金经济与管理，2004(4).4345.

[25]程世东，荣建，刘小明.城市物流园区及规划[[J].城市交通，2004.(3):21-23.

[26]贺登才.10大问题制约公路货运发展交通管理新政意见征询中[[J].物流技术与应用.2009(4).