Funding for this research was provided by:
Department of Science & Technology (DST) of India (DST/INSPIRE Fellowship/2015/IF150209 dated 01/10/2015.)
Portuguese Foundation for Science and Technology (within project UID/MAT/04106/2013)
The Portuguese Foundation for Science and Technology (“FCT-Fundação para a Ciência e a Tecnologia”), through the CIDMA-Center for Research and Development in Mathematics and Applications, University (within project UID/MAT/04106/2013)
Article History
Received: 10 January 2018
Accepted: 16 January 2020
First Online: 30 January 2020