[Xiong, Pei-Ying] Hunan City Univ, Coll Sci, Yiyang 413000, Peoples R China.
[Hamid, Aamir; Qayyum, Sumaira] Quaid I Azam Univ, Dept Math, Islamabad 45320, Pakistan.
[Chu, Yu-Ming] Huzhou Univ, Dept Math, Huzhou 313000, Peoples R China.
[Chu, Yu-Ming] Changsha Univ Sci & Technol, Hunan Prov Key Lab Math Modeling & Anal Engn, Changsha 410114, Peoples R China.
[Khan, M. Ijaz] Riphah Int Univ I 14, Dept Math & Stat, Islamabad 44000, Pakistan.