1. Istituto per Applicazioni del Calcolo ‘M.Picone’, National Research Council (CNR), Via Amendola 122/D, 70126 Bari, Italy
2. Istituto di Nanotecnologie ‘NANOTEC’, National Research Council (CNR), Via Monteroni 122/D, 73100 Lecce, Italy
3. Centrum Badan Kosmicznych PAN, Bartycka 18a, 00-716 Warszawa, Poland