1
University of L'Aquila, Italy (UAQ)
Department of Information Engineering, Computer Science and Mathematics,
via Vetoio (Coppito), 1 – 67100 L’Aquila (Italy)
2
Autonomous University of Barcelona, Catalonia - Spain (UAB)
Departament de Matemàtiques, Edifici Cc - Campus UAB 08193 Bellaterra – Catalonia
3
Gdansk University of Technology, Poland (GUT)
Department of Solid State Physics, G. Narutowicza 11/12, 80-952 Gdansk, Poland
4
University of Hamburg, Germany (UHH)
Department of Mathematics
Bundesstr. 55
20146 Hamburg - Germany
5
University of Nice - Sophia Antipolis, France (UNS)
Laboratoire J.A.Dieudonné
Parc Valrose,
France-06108 NICE Cedex 2