[1] Univ Malakand Chakdara Dir L, Dept Math, Timergara 18000, Khyber Pakhtunk, Pakistan
[2] Prince Sultan Univ, Dept Math & Sci, POB 66833, Riyadh 11586, Saudi Arabia
[3] China Med Univ, Dept Med Res, Taichung 40402, Taiwan
[4] Sefako Makgatho Hlth Sci Univ, Sch Sci & Technol, Dept Math & Appl Math, Ga Rankuwa, South Africa