1. Department of Civil, Energy, Environmental and Material Engineering (DICEAM), University of Reggio Calabria, Via Zehender, Località Feo di Vito, 89122 Reggio Calabria, Italy
2. Department of Mathematics and Computer Sciences, Physical Sciences and Earth Sciences (MIFT), University of Messina, Viale Ferdinando Stagno d’Alcontres, 98166 Messina, Italy
3. Department of Mathematics and Computer Science, University of Palermo, Via Archirafi 34, 90123 Palermo, Italy