KUČERA, Antonín and Richard MAYR. Why is Simulation Harder Than Bisimulation? L. Brim, P. Jancar, M. Kretinsky, A. Kucera (Eds.). In
Proceedings of 13th International Conference on Concurrency Theory (CONCUR 2002). Berlin: Springer, 2002, p. 594-609. ISBN 3-540-44043-7.