Authors
Carl-Anders Johansson
Luleå University of Technology, 971 87, Luleå, Sweden
Urko Leturiondo
Luleå University of Technology 971 87,, Luleå, Sweden
IK4-Ikerlan, Arrasate-Mondragón, P°. J. Mª. Arizmendiarrieta, 2 20500 Arrasate-, Mondragón, Spain