1. MTA SZTAKI Computer and Automation Research Institute; H-1518 Budapest Hungary
2. Department of Software Engineering; University of Szeged; H-6720 Szeged, Dugonics ter 13 Hungary
3. Biological Research Center; H-6701 Szeged Hungary
4. University of Westminster; 115 New Cavendish Street, London W1W 6UW UK