东北大学学报(社科版),2006,(s1):64-66112. Yi Pingtao, Guo Yajun, Zhang Danning. Density Weighted Averaging Middle Operator[C]. Proceedings of 2006 International Conference on Management Science & Engineering, Harbin,
ICMeCG 2009. 2009.9, EI检索.[3]LIU Bin, LIU Chao. Research on the Competitiveness of China’s Ports. 9th International Conference of Chinese Transportation Professionals,