Hywel R. Dunn-Davies Jim Cunningham Shamimabi Paurobally Modularity and Composition in Propositional Statecharts. 98-103 2006 conf/diagrams/2006 Diagrams http://dx.doi.org/10.1007/11783183_12 db/conf/diagrams/diagrams2006.html#Dunn-DaviesCP06