1. Institut für Informatik University of Heidelberg Heidelberg Germany
2. Faculty of Informatics Masaryk University Brno Czech Republic
3. Mathematics Institute, DIMAP and Department of Computer Science University of Warwick Coventry UK
4. Faculty of Mathematics, Natural Sciences and Information Technologies University of Primorska Koper Slovenia
5. Department of Mathematics, Faculty of Nuclear Sciences and Physical Engineering Czech Technical University in Prague Prague Czech Republic