[Li, Yanjun] Anhui Univ Finance & Econ, Inst Stat & Appl Math, Bengbu 233030, Anhui, Peoples R China.
[Peng, Jie; Li, Yanjun] Shanghai Normal Univ, Math & Sci Coll, Shanghai 200234, Peoples R China.
[Kan, Haibin] Fudan Univ, Sch Comp Sci, Key Lab Intelligent Informat Proc, Shanghai 200433, Peoples R China.
[Mesnager, S; Mesnager, Sihem] Univ Paris VIII, Dept Math, F-93526 St Denis, France.
[Mesnager, Sihem] Univ Sorbonne Paris Nord, LAGA, Lab Geometry Anal & Applicat, CNRS,UMR 7539, F-93430 Villetaneuse, France.