Depke, R., Engels, G., &; Küster, J. (2000). On the Integration of Roles in the UML. University of Paderborn, Department of Computer Science.

Depke, R., Heckel, R., &; Küster, J. (2000). Modeling Agent-Based Systems with Graph Transformation. University of Paderborn, Department of Computer Science.

Engels, G., Hücking, R., Sauer, S., &; Wagner, A. (1999). UML Collaboration Diagrams and Their Transformation to Java. University of Paderborn, Department of Computer Science.

Andries, M., Engels, G., Habel, A., Hoffmann, B., Kreowski, H.-J., Kuske, S.,  Taentzer, G. (1996). Graph Transformation for Specification and Programming. University of Bremen, Department of Mathematics and Computer Science.

Pletat, U., Engels, G., &; Ehrich, H.-D. (1981). Operational Semantics of Algebraic Specifications with Conditional Equations. University of Dortmund, Department of Computer Science.