Ekström, Sven-Erik http://orcid.org/0000-0002-7875-7543
Garoni, Carlo http://orcid.org/0000-0001-9720-092X
Funding for this research was provided by:
Istituto Nazionale di Alta Matematica ”Francesco Severi” (PCOFUND-GA-2012-600198)
Article History
Received: 22 August 2017
Accepted: 4 March 2018
First Online: 24 March 2018