@bookDepke_Engels_Küster_2000, title=On the Integration of Roles in the UML, publisher=University of Paderborn, Department of Computer Science, author=Depke, Ralph and Engels, Gregor and Küster, Jochen, year=2000 

@bookDepke_Heckel_Küster_2000, title=Modeling Agent-Based Systems with Graph Transformation, publisher=University of Paderborn, Department of Computer Science, author=Depke, Ralph and Heckel, Reiko and Küster, Jochen, year=2000 

@bookEngels_Hücking_Sauer_Wagner_1999, title=UML Collaboration Diagrams and Their Transformation to Java, publisher=University of Paderborn, Department of Computer Science, author=Engels, Gregor and Hücking, Roland and Sauer, Stefan and Wagner, Annika, year=1999 

@bookAndries_Engels_Habel_Hoffmann_Kreowski_Kuske_Plump_Schürr_Taentzer_1996, title=Graph Transformation for Specification and Programming, publisher=University of Bremen, Department of Mathematics and Computer Science, author=Andries, Marc and Engels, Gregor and Habel, Annegret and Hoffmann, Berthold and Kreowski, Hans-Jörg and Kuske, Sabine and Plump, Detlef and Schürr, Andy and Taentzer, Gabriele, year=1996 

@bookPletat_Engels_Ehrich_1981, title=Operational Semantics of Algebraic Specifications with Conditional Equations, publisher=University of Dortmund, Department of Computer Science, author=Pletat, Udo and Engels, Gregor and Ehrich, Hans-Dietrich, year=1981