[Chang, Hao] Cent China Normal Univ, Sch Math & Stat, 152 Luoyu Rd, Wuhan 430079, Peoples R China.
[Chang, Hao] Cent China Normal Univ, Hubei Key Lab Math Sci, 152 Luoyu Rd, Wuhan, Peoples R China.
[Shu, Bin] East China Normal Univ, Sch Math Sci, Key Lab Math & Engn Applicat, Minist Educ, 500 Dongchuan Rd, Shanghai 200241, Peoples R China.
[Shu, Bin] East China Normal Univ, Shanghai Key Lab PMMP, 500 Dongchuan Rd, Shanghai 200241, Peoples R China.
[Yao, Yu-Feng] Shanghai Maritime Univ, Dept Math, 1550 Haigang Ave, Shanghai 201306, Peoples R China.