John Fearnley, Marcin Jurdzinski. Reachability in Two-Clock Timed Automata Is PSPACE-Complete. In Fedor V. Fomin, Rusins Freivalds, Marta Z. Kwiatkowska, David Peleg, editors, Automata, Languages, and Programming - 40th International Colloquium, ICALP 2013, Riga, Latvia, July 8-12, 2013, Proceedings, Part II. Volume 7966 of Lecture Notes in Computer Science, pages 212-223, Springer, 2013. [doi]
Abstract is missing.