Leonardi, Gian Paolo http://orcid.org/0000-0003-1944-312X
Saracco, Giorgio http://orcid.org/0000-0001-9675-2757
Funding for this research was provided by:
Istituto Nazionale di Alta Matematica "Francesco Severi"
Article History
Received: 12 July 2017
Accepted: 8 February 2018
First Online: 23 February 2018
Free to read: This content has been made available to all.