[Li, Yun-Xiang] Hunan City Univ, Sch Sci, Yiyang 413000, Peoples R China.
[Hamid, Aamir] Quaid I Azam Univ, Dept Math, Islamabad 45320, Pakistan.
[Khan, M. Ijaz] Riphah Int Univ, Dept Math & Stat, Islamabad 44000, Pakistan.
[Elmasry, Yasser; Qayyum, Sumaira] King Khalid Univ, Coll Sci, Dept Math, Abha 61413, Saudi Arabia.
[Madhukesh, J. K.; Prasannakumara, B. C.; Kumar, R. S. Varun] Davangere Univ, Dept Math, Shivagangotri Davangere 577002, Karnataka, India.