Branislav Rovan Peter Vojtás Mathematical Foundations of Computer Science 2003, 28th International Symposium, MFCS 2003, Bratislava, Slovakia, August 25-29, 2003, Proceedings MFCS Lecture Notes in Computer Science 2747 Springer 2003 3-540-40671-9 db/conf/mfcs/mfcs2003.html