Paul Boehm Harald-Reto Fonio Annegret Habel Amalgamation of Graph Transformations with Applications to Synchronization. 267-283 1985 conf/tapsoft/1985-1 TAPSOFT, Vol.1 db/conf/tapsoft/tapsoft85-1.html#BoehmFH85 http://dx.doi.org/10.1007/3-540-15198-2_17