[LI, Yong-min] Huzhou Univ, Dept Math, Huzhou 313000, Peoples R China.
[Rashid, Saima] Govt Coll Univ, Dept Math, Faisalabad 38000, Pakistan.
[Hammouch, Zakia] Thu Dau Mot Univ, Div Appl Math, Binh Duong Province, Vietnam.
[Hammouch, Zakia] China Med Univ, Dept Med Res, China Med Univ Hosp, Taichung 40402, Taiwan.
[Hammouch, Zakia] Moulay Ismail Univ, Ecole Normale Super, Meknes 5000, Morocco.