Costarelli, Danilo http://orcid.org/0000-0001-8834-8877
Spigler, Renato
Funding for this research was provided by:
Istituto Nazionale di Alta Matematica "Francesco Severi"
Dipartimento di Matematica e Informatica dell’Università degli Studi di Perugia
Article History
Received: 23 October 2017
Revised: 29 June 2018
Accepted: 6 July 2018
First Online: 13 July 2018