SOFSEM 2009: Theory and Practice of Computer Science : 35th Conference on Current Trends in Theory and Practice of Computer Science, .pindleruv Mlýn, Czech Republic, January 24-30, 2009. Proceedings - Mogens Nielsen, Antonín Ku.era, Peter Bro Miltersen, Catuscia Palamidessi, Petr T.ma, Frank Valencia ((Lecture Notes in Computer Science))