[1] Vel Tech High Tech Dr Rangarajan Dr Sakunthala En, Chennai 600062, Tamil Nadu, India
[2] Alagappa Univ, Ramanujan Ctr Higher Math, Karaikkudi 630004, Tamil Nadu, India
[3] Prince Sultan Univ, Dept Math & Gen Sci, Riyadh 12435, Saudi Arabia
[4] Southeast Univ, Sch Math, Nanjing 211189, Peoples R China
[5] Maejo Univ, Fac Sci, Dept Math, Chiang Mai, Thailand