Ebert, Jürgen, and Gregor Engels. Ein Konzept Zur Beschreibung von Software-Architekturen. EWH Koblenz, 1988.

Engels, Gregor, et al. “Die Benutzerschnittstelle Einer Integrierten Modula-2 Programmentwicklungsumgebung.” Proceedings of GI-Workshop Sprachspezifische Programmierumgebungen, Darmstadt, Germany, 1988.

Engels, Gregor, and Andy Schürr. “A Hybrid Interpreter in a Software Development Environment.” Proceedings of the 1st European Software Engineering Conference (ESEC ’87), Strasbourg (France), vol. 289, Springer, 1987, pp. 80–88.

Engels, Gregor, et al. “On the Structure of Structure-Oriented Editors for Different Applications.” Proceedings of the ACM SIGSOFT/SIGPLAN Software Engineering Symposium on Practical Software Development Environments, Palo Alto, USA, vol. 22, no. 1, ACM SIGPLAN Notices, 1987, pp. 190–98.

Engels, Gregor, et al. “Graph Grammar Engineering: A Software Specification Method.”dx.doi.org/10.1007/3-540-18771-5__Proceedings of the 3rd International Workshop on Graph-Grammars and Their Application to Computer Science, Warrenton, VA (USA), vol. 291, Springer, 1987, pp. 186–201, doi:dx.doi.org/10.1007/3-540-18771-5.

Engels, Gregor, et al. “On the Structure of an Incremental and Integrated Software Development Environment.” Proceedings of the 19th Hawaii International Conference on System Sciences, Hawaii, USA, vol. 2a, 1986, pp. 585–97.

Engels, Gregor, and Andrea Sandbrink. “Experiences with a Hybrid-Interpreter Based on Incremental Compilation Techniques.” Proceedings of the Workshop on Compiler Compilers and Incremental Compilation Techniques, Bautzen, vol. 12, Berlin(Ost): Akademie der Wissenschaften der DDR, 1986, pp. 172–84.

Engels, Gregor. Graphen Als Zentrale Datenstrukturen in Einer Software-Entwicklungsumgebung. 1986.

Engels, Gregor, and Wilhelm Schäfer. “Graph Grammar Engineering: A Method Used for the Development of an Integrated Programming Support Environment.” Proceedings of the International Joint Conference on Theory and Practice of Software Development (TAPSOFT 1985), Berlin (Germany), vol. 186, Springer, 1985, pp. 179–93.

Engels, Gregor, and Wilhelm Schäfer. “The Design of an Adaptive and Portable Programming Support Environment.” Proceedings of the International Computing Symposium, Amsterdam (The Netherlands), 1985.

Nagl, Manfred, et al. “Software Specification by Graph Grammars.”dx.doi.org/10.1007/BFb0000113__Proceedings of the 2nd International Workshop on Graph-Grammars and Their Application to Computer Science, Osnabrück (Germany), vol. 153, Springer, 1983, pp. 267–87, doi:dx.doi.org/10.1007/BFb0000113.

Engels, Gregor, et al. “Software Specification Using Graph Grammars.”http://dx.doi.org/10.1007/BF02251236__Computing, vol. 31, no. 4, 1983, pp. 317–46, doi:http://dx.doi.org/10.1007/BF02251236.

Engels, Gregor, et al. “An Operational Semantics for Specifications of Abstract Data Types with Error Handling.”http://dx.doi.org/10.1007/BF00265557__Acta Informatica, vol. 9, no. 3, 1983, pp. 235–54, doi:http://dx.doi.org/10.1007/BF00265557.

Engels, Gregor, and Wilhelm Schäfer. “Specification of a Programming Support Environment by Graph Grammars.” Proceedings of the Conference on Graphtheoretic Concepts in Computer Science (WG), München (Germany), Hanser, 1982, pp. 47–62.

Pletat, Udo, et al. “An Operational Approach to Conditional Algebraic Specifications.” Proceedings of the 7eme Colloque Sur Les Arbres En Algebre et En Programmation, Lille (France), vol. 82, 1982, pp. 254–70.

Engels, Gregor, et al. Handling Errors and Exceptions in the Algebraic Specifications of Data Types. University of Osnabrück, 1981.

Pletat, Udo, et al. Operational Semantics of Algebraic Specifications with Conditional Equations. University of Dortmund, Department of Computer Science, 1981.