[1] Koneru Lakshmaiah Educ Fdn, Dept Math, Hyderabad 500043, Telangana, India
[2] RGM Coll Engn & Technol, Dept Math, Nandyal 518501, Andhra Pradesh, India
[3] Yogi Vemana Univ, Dept Appl Math, Kadapa 516005, Andhra Pradesh, India
[4] Chennai Inst Technol, Ctr Computat Modeling, Chennai 600069, Tamil Nadu, India