SOFSEM 2007: Theory and Practice of Computer Science 33rd Conference on Current Trends in Theory and Practice of Computer Science, Harrachov, Czech Republic, January 20-26, 2007. Proceedings - Leeuwen, Jan van; Italiano, Giuseppe F.; Hoek, Wiebe van der; Meinel, Christoph; Sack, Harald; Plášil, František (Springer Berlin Heidelberg, 2007)