1. a Institut für Mathematik B, Technische Universität Graz , Steyrergasse 30, Graz, A-8010, Austria
2. b Department of Applied Mathematics , University of Miskolc , H-3515 Miskolc-Egyetemváros, Hungary
3. c Technikum Joanneum Construction Engineering and Management , Alte Poststraße 149, Graz, A-8020, Austria
4. d BT Laboratories, Admin 2 PP5, Martlesham Heath , Ipswich IP5 3RE, United Kingdom