Deqiang Chen Jie Zheng Xiaoqian Wu Computer Simulation and Word-Updating Dynamical Systems (WDS) on Digraphs. 209-216 2008 ICIC (2) http://dx.doi.org/10.1007/978-3-540-85984-0_26 conf/icic/2008-2 db/conf/icic/icic2008-2.html#ChenZW08