Funding for this research was provided by:
Fondazione Cassa di Risparmio di Perugia
Gruppo Nazionale per l’Analisi Matematica, la Probabilità e le loro Applicazioni
Università degli Studi di Perugia
Article History
Received: 24 March 2020
Revised: 29 June 2020
Accepted: 8 February 2021
First Online: 23 February 2021
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.