1. Department of Mathematics, Avvaiyar Government College for Women, Karaikal, India
2. Department of Mathematics, National Institute of Technology Puducherry, Karaikal, India
3. Department of Mathematics, Maulana Abul Kalam Azad University of Technology, Kolkata, India
4. CITMAga, Departamento de Estatística, Análise Matemática e Optimización, Universidade de Santiago de Compostela, Spain