1. Department of Industrial and Information Engineering and Economics, University of L’Aquila, Via G. Gronchi 18, I-67100 L’Aquila, Italy
2. UdR INSTM of L’Aquila, I-67100 L’Aquila Italy
3. Department of Physical and Chemical Sciences, University of L’Aquila, Via Vetoio, 67100 L’Aquila (AQ), Italy