1. Department of Mathematics, University College of Engineering, Osmania University, Hyderabad 500007, India
2. Department of Mathematics, Government Degree College for Women, Begumpet, Hyderabad 500007, India
3. School of Physical Sciences and Nanotechnology, Yachay Tech University, Urcuquí 00119, Ecuador
4. Instituto de Alta Investigación CEDENNA, Universidad de Tarapacá, Casilla 7D, Arica, Chile
5. Max Planck Institute for Polymer Research, Mainz D 55021, Germany