Institution: | 1. Department of Mathematics and Statistics, The University of North Carolina at Greensboro, NC 27402, USA;2. NTIS New Technologies for the Information Society, European Centre of Excellence, Faculty of Applied Sciences, University of West Bohemia, Univerzitní 8, 306 14 Plzeň, Czech Republic;3. KMA-FAV, Západo?eská Univerzita v Plzni, Univerzitní 22, CZ-30614 Plzeň, Czech Republic |