Hartmut Ehrig Robert Geisler Marcus Klar Julia Padberg Horizontal and Vertical Structuring Techniques for Statecharts. 181-195 1997 conf/concur/1997 CONCUR db/conf/concur/concur1997.html#EhrigGKP97 http://dx.doi.org/10.1007/3-540-63141-0_13