[Zhang, Xiao-Hong] Hunan City Univ, Coll Sci, Yiyang 413000, Peoples R China.
[Shah, Rasool] Abdul Wali Khan Univ Mardan, Dept Math, Mardan 23200, Pakistan.
[Saleem, S.] King Khalid Univ, Coll Sci, Dept Math, Abha 61413, Saudi Arabia.
[Shah, Nehad Ali; Chung, Jae Dong] Sejong Univ, Dept Mech Engn, Seoul 05006, South Korea.
[Shah, Nehad Ali] Lahore Leads Univ, Dept Math, Lahore, Pakistan.