CollegeofEconomics;
SichuanUniversity.Chengdu610055;
P.R.China//SchoolofManagernent;
UnlversizyofElectronicSciencearidTechnologyofChina.Chengdu610054;
P.R.China;
CollegeofEconomics;
SichuanUniversity.Chengdu610055;
P.R.China//SchoolofEconomics;
SouthwestUniversityforNationality.Chengdu610040;
P.R.China;