1. Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy
2. Department of Economics and Law, Università degli Studi di Macerata, Macerata, Italy
3. Department of Computer Science and Numerical Analysis, University of Córdoba, Córdoba, Spain
4. Communication and International Relations, Department of Political Science, Università degli Studi di Macerata, Macerata, Italy