[Song, Ying-Qing] Hunan City Univ, Coll Sci, Yiyang 413000, Peoples R China.
[Raza, Ali; Farid, Saadia] Univ Engn & Technol, Dept Math, Lahore 54890, Pakistan.
[Al-Khaled, Kamel] Jordan Univ Sci & Technol, Dept Math & Stat, POB 3030, Irbid 22110, Jordan.
[Khan, M. Ijaz] Dept Math & Stat, Riphah Int Univ I-14, Islamabad 44000, Pakistan.
[Khan, M. Ijaz] King Abdulaziz Univ, Fac Sci, Dept Math, Nonlinear Anal & Appl Math NAAM Res Grp, POB 80257, Jeddah 21589, Saudi Arabia.