1. a University of Maribor, Faculty of Mechanical Engineering , Smetanova ulica 17, SI – 2000, Maribor, Slovenia Phone: Fax: E-mail:
2. b University of Maribor, Faculty of Mechanical Engineering , Smetanova ulica 17, SI – 2000, Maribor, Slovenia Phone: Fax: E-mail:
3. c University of Maribor, Faculty of Mechanical Engineering , Smetanova ulica 17, SI – 2000, Maribor, Slovenia Phone: Fax: E-mail: