Funding for this research was provided by:
Fundação para a Ciência e a Tecnologia (UID/MAT/04459/2020, UIDB/00013/2020,)
Fundação para a Ciência e a Tecnologia (UIDP/00013/2020)
Article History
Received: 21 April 2020
Accepted: 27 November 2020
First Online: 23 December 2020