[1] Sultan Qaboos Univ, Dept Phys, Coll Sci, POB 36, Muscat 123, Oman
[2] Islamia Univ Bahwalpur, Dept Math, Bahwalpur, Pakistan
[3] COMSATS Inst Informat Technol, Dept Math, Sahiwal 57000, Pakistan
[4] Univ Kashmir, Dept Elect & Commun Engn, Srinagar 190006, Kashmir, India
[5] Eurasian Natl Univ, Eurasian Int Ctr Theoret Phys, Astana 010008, Kazakhstan
[6] Eurasian Natl Univ, Dept Gen & Theoret Phys, Astana 010008, Kazakhstan