@articleHeckel_Corradini_Ehrig_Löwe_1996, title=Horizontal and Vertical Structuring of Typed Graph Transformation Systems, volume=6, number=6, journal=Mathematical Structures in Computer Science, author=Heckel, Reiko and Corradini, Andrea and Ehrig, Hartmut and Löwe, Michael, year=1996, pages=613–648 

@articleAndries_Engels_1996, title=A Hybrid Query Language for the Extended Entity Relationship Model, volume=7, DOI=http://dx.doi.org/10.1006/jvlc.1996.0017, number=3, journal=Journal of Visual Languages and Computing, author=Andries, Marc and Engels, Gregor, year=1996, pages=321–352 

@inbookEngels_Nagl_Schäfer_Westfechtel_1996, place=Berlin/Heidelberg, series=LNCS, title=Tight Integration on One Document: The Programming Environment, volume=1170, booktitle=Building Tightly Integrated Software Development Environments: The IPSEN Approach, publisher=Springer, author=Engels, Gregor and Nagl, Manfred and Schäfer, Wilhelm and Westfechtel, Bernhard, year=1996, pages=170–177, collection=LNCS 

@inproceedingsHeckel_Müller_Taentzer_Wagner_1995, series=Technical Report, title=Attributed Graph Transformations with Controlled Application of Rules, number=B-19, booktitle=Proceedings of the Colloquium on Graph Transformation and its Application in Computer Science, publisher=Universitat de les Illes Balears, author=Heckel, Reiko and Müller, Jürgen and Taentzer, Gabriele and Wagner, Annika, year=1995, collection=Technical Report 

@inproceedingsThoben_Appelrath_Sauer_1995, place=Berlin/Heidelberg, series=Studies in Classification, Data Analysis, and Knowledge Organization, title=Record Linkage of Anonymous Data by Control Numbers, booktitle=Proceedings of the 18th Annual Conference of the Gesellschaft für Klassifikation, Oldenburg (Germany), publisher=Springer, author=Thoben, Wilfried and Appelrath, Hans-Jürgen and Sauer, Stefan, year=1995, pages=412–419, collection=Studies in Classification, Data Analysis, and Knowledge Organization 

@inproceedingsHeckel_1995, series=Technical Report, title=Embedding of Conditional Graph Transformations, number=B-19, booktitle=Proceedings of the Colloquium on Graph Transformation and its Application in Computer Science, publisher=Universitat de les Illes Balears, author=Heckel, Reiko, year=1995, collection=Technical Report 

@bookConrad_Gajewsky_Holl-Biniasz_Rudolf_Demuth_Weber_Heckel_Müller_Taentzer_Wagner_1995, title=Graphische Spezifikation ausgewählter Teile von AGG - einem algebraischen Graphgrammatiksystem, author=Conrad, Mirko and Gajewsky, Magdalena and Holl-Biniasz, Rainer and Rudolf, Michael and Demuth, Jochen and Weber, Stephan and Heckel, Reiko and Müller, Jürgen and Taentzer, Gabriele and Wagner, Annika, year=1995 

@bookEbert_Engels_1995, place=Koblenz, title=Specialization of Object Life Cycle Definitions, publisher=University of Koblenz-Landau, author=Ebert, Jürgen and Engels, Gregor, year=1995 

@bookEngels_Schürr_1995, title=Encapsulated Hierarchical Graphs, Graph Types, and Meta Types, publisher=Vakgroep Informatica, Rijksuniversiteit Leiden, author=Engels, Gregor and Schürr, Andy, year=1995 

@inproceedingsGroenewegen_Engels_1995, place=Berlin/Heidelberg, series=LNCS, title=Coordination by Behavioural Views and Communication Patterns, volume=913, DOI=http://dx.doi.org/10.1007/3-540-59205-9_56, booktitle=Proceedings of the 4th European Workshop on Software Process Technology (EWSPT 1995), Noordwijkerhout (The Netherlands), publisher=Springer, author=Groenewegen, Luuk and Engels, Gregor, year=1995, pages=189–192, collection=LNCS 

@inproceedingsCorradini_Heckel_1995, series=Electronic Notes in Theoretical Computer Science , title=A Compositional Approach to Structuring and Refinement of Typed Graph Grammars, volume=2, booktitle=Proceedings of the Joint COMPUGRAPH/SEMAGRAPH Workshop on Graph Rewriting and Computation (SEGRAGRA 1995), Volterra (Italy), publisher=Elsevier, author=Corradini, Andrea and Heckel, Reiko, year=1995, pages=46–55, collection=Electronic Notes in Theoretical Computer Science  

@inproceedingsBardohl_Bardohl_Castro_Ehrig_Heckel_Ribeiro_Nunes_Martini_1995, series=Bilateral Seminars of the International Bureau, title=GRAPHIT: Graphical Support and Integration of Formal and Semiformal Methods for Software Specification and Development, volume=26, booktitle=Proceedings of the 3rd German-Brazilian Workshop on Information Technology (1995), Berlin (Germany), publisher=Forschungszentrum Jülich GmbH, author=Bardohl, Bernhard and Bardohl, Roswitha and Castro, Paulo and Ehrig, Hartmut and Heckel, Reiko and Ribeiro, Leila and Nunes, Daltro and Martini, Alfio, year=1995, collection=Bilateral Seminars of the International Bureau 

@inproceedingsEngels_Schürr_1995, place=Amsterdam, The Netherlands, series=Electronic Notes in Theoretical Computer Science, title=Encapsulated Hierarchical Graphs, Graph Types, and Meta Types, DOI=http://dx.doi.org/10.1016/S1571-0661(05)80186-0, booktitle=Proceedings of the Joint COMPUGRAPH/SEMAGRAPH Workshop on Graph Rewriting and Computation (SEGRAGRA 1995), Volterra (Italy), publisher=Elsevier, author=Engels, Gregor and Schürr, Andy, year=1995, pages=101–109, collection=Electronic Notes in Theoretical Computer Science 

@inproceedingsHeckel_Wagner_1995, series=Electronic Notes in Theoretical Computer Science, title=Ensuring Consistency of Conditional Graph Grammars - A constructive Approach, volume=2, DOI=http://dx.doi.org/10.1016/S1571-0661(05)80188-4, booktitle=Proceedings of the Joint COMPUGRAPH/SEMAGRAPH Workshop on Graph Rewriting and Computation (SEGRAGRA 1995), Volterra (Italy), publisher=Elsevier, author=Heckel, Reiko and Wagner, Annika, year=1995, pages=118–126, collection=Electronic Notes in Theoretical Computer Science 

@bookEhrich_Engels_Paredaens_Wegner_1994, series=Dagstuhl-Seminar-Report, title=Fundamentals of Object-Oriented Languages, Systems, and Methods, volume=95, publisher=Schloss Dagstuhl, Leibniz Center for Informatics, year=1994, collection=Dagstuhl-Seminar-Report 

@bookCuny_Ehrig_Engels_Rozenberg_1994, place=Berlin/Heidelberg, series=LNCS, title=Graph Gramars and Their Application to Computer Science, 5th International Workshop (1994), Selected Papers, volume=1073, DOI=http://dx.doi.org/10.1007/3-540-61228-9, publisher=Springer, year=1994, collection=LNCS 

@inproceedingsThoben_Appelrath_Rettig_Sauer_1994, place=München, title=Berücksichtigung von Datenschutzaspekten in einem bevölkerungsbezogenen Krebsregister, booktitle=Proceedings of the conference on Medizin und Information, Biometrie und Epidemiologie (GMDS 1994), Dresden (Germany), publisher=MMV Medizin Verlag, author=Thoben, Wilfried and Appelrath, Hans-Jürgen and Rettig, Jens and Sauer, Stefan, year=1994, pages=88–90 

@inproceedingsEbert_Engels_1994, place=Berlin/Heidelberg, title=Structural and Behavioural Views on OMT-Classes, volume=858, booktitle=Proceedings of the International Symposium on Object-Oriented Methodologies and Systems (ISOOMS 1994), Palermo (Italy), publisher=Springer, author=Ebert, Jürgen and Engels, Gregor, year=1994, pages=142–157 

@inproceedingsEngels_Kappel_1994, title=Object-Oriented System Development: Will the New Approach Solve Old Problems?, volume=3, booktitle=Proceedings of the IFIP 13th World Computer Congress on Information Processing, Hamburg (Germany), publisher=Elsevier, author=Engels, Gregor and Kappel, Gerti, year=1994, pages=434–441 

@inproceedingsEngels_Ehrig_1994, series=Technical Report , title=Towards a Module Concept for Graph Transformation Systems: The Software Engineering Perspective, volume=B-19, booktitle=Proceedings Colloquium on Graph Transformation and its Application in Computer Science, publisher=Universitat de les Illes Balears, Departament de Ci, author=Engels, Gregor and Ehrig, Hartmut, year=1994, collection=Technical Report  

@bookEbert_Engels_1994, title=Observable or Invocable Behaviour - You Have to Choose, publisher=Vakgroep Informatica, Rijksuniversiteit Leiden, author=Ebert, Jürgen and Engels, Gregor, year=1994 

@inproceedingsAndries_Engels_1994, place=Berlin/Heidelberg, series=LNCS, title=Syntax and Semantics of Hybrid Database Languages, volume=776, DOI=http://dx.doi.org/10.1007/3-540-57787-4_2, booktitle=Proceedings of the International Workshop on Graph Transformations in Computer Science (1993), Dagstuhl (Germany), publisher=Springer, author=Andries, Marc and Engels, Gregor, year=1994, pages=19–36, collection=LNCS 

@inproceedingsEngels_Groenewegen_1994, place=Berlin/Heidelberg, series=LNCS, title=Specification of coordinated behaviour by SOCCA, DOI=http://dx.doi.org/10.1007/3-540-57739-4_19, booktitle=Proceedings of the Third European Workshop on Software Process Technology (EWSPT 1994), Villard de Lans (France), publisher=Springer, author=Engels, Gregor and Groenewegen, Luuk, year=1994, pages=128–151, collection=LNCS 

@inproceedingsEngels_Löhr_1994, place=Berlin/Heidelberg, title=Visual Specification of Complex Database Actions, booktitle=Proceedings of the 2nd International East/West Database Workshop, Klagenfurt (Germany), publisher=Springer, author=Engels, Gregor and Löhr, Perdita, year=1994, pages=303–314 

@articleLöhr-Richter_Engels_1994, title=Visuelles Spezifizieren von komplexen Aktionen auf Datenbankstrukturen, volume=13, journal=GI-Datenbank Rundbrief, author=Löhr-Richter, Perdita and Engels, Gregor, year=1994, pages=33–35 

@inbookEbert_Engels_1994, title=Design Representation, booktitle=Encyclopedia of Software Engineering, publisher=John Wiley &; Sons, Inc., author=Ebert, Jürgen and Engels, Gregor, year=1994, pages=382–394 

@inbookEngels_Groenewegen_1994, place=Taunton, title=SOCCA: Specifications of Coordinated and Cooperative Activities, booktitle=Software Process Modelling and Technology, publisher=Research Studies Press, author=Engels, Gregor and Groenewegen, Luuk, year=1994, pages=71–102 

@inproceedingsEngels_Verrijn-Stuart_1993, series=Reihe 10: Informatik/Kommunikationstechnik, title=Integrationsaspekte bei verteilter Software-Entwicklung, number=251, booktitle=Fortschritt-Berichte VDI, publisher=VDI Verlag, author=Engels, Gregor and Verrijn-Stuart, A.A., year=1993, pages=45–53, collection=Reihe 10: Informatik/Kommunikationstechnik 

@bookAndries_Engels_1993, title=A Hybrid Query Language for the Extended Entity Relationship Model, publisher=Vakgroep Informatica, Rijksuniversiteit Leiden, author=Andries, Marc and Engels, Gregor, year=1993 

@bookEhrig_Engels_1993, title=Towards a Module Concept for Graph Transformation Systems, publisher=Vakgroep Informatica, Rijksuniversiteit Leiden, author=Ehrig, Hartmut and Engels, Gregor, year=1993 

@bookEngels_Rozenberg_1993, title=Abstracts COMPUGRAPH II Workshop, publisher=Vakgroep Informatica, Rijksuniversiteit Leiden, author=Engels, Gregor and Rozenberg, Grzegorz, year=1993 

@inproceedingsEngels_Groenewegen_1993, place=Washington, DC, USA, title=Modular, Visual Specifications of Software Processes, booktitle=Proceedings of the Workshop on Software Process (ISPW 1993), Wadern (Germany), publisher=IEEE Computer Society, author=Engels, Gregor and Groenewegen, Luuk, year=1993, pages=66–68 

@inproceedingsKoopman_Groenewegen_Engels_1992, title=Functional Description of Parallel Processes, booktitle=Proceedings of the conference SION Computing Science in the Netherlands (CSN ’92), The Netherlands, author=Koopman, Pieter and Groenewegen, Luuk and Engels, Gregor, year=1992, pages=156–167 

@bookEngels_1992, title=Visual Specifications of Conceptual Database Schemata (Abstract), publisher=Leiden University, author=Engels, Gregor, year=1992 

@inproceedingsEngels_Löhr-Richter_1992, place=Washington, DC, USA, title=CADDY: A Highly Integrated Environment to Support Conceptual Database Design, booktitle=Proceedings of the Fifth International Workshop on Computer-Aided Software Engineering (CASE 1992), Montreal (Canada), publisher=IEEE Computer Society, author=Engels, Gregor and Löhr-Richter, Perdita, year=1992, pages=19–22 

@inproceedingsEngels_Groenewegen_1992, place=Berlin/Heidelberg, series=LNCS, title=Specification of Coordinated Behaviour in the Software Development Process, volume=635, DOI=http://dx.doi.org/10.1007/BFb0017495, booktitle=Proceedings of the Second European Workshop on Software Process Technology (EWSPT 92), Trondheim, Norway, publisher=Springer, author=Engels, Gregor and Groenewegen, Luuk, year=1992, pages=58–60, collection=LNCS 

@articleHohenstein_Engels_1992, title=SQL/EER - Syntax and Semantics of an Entity-Relationship-Based Query Language, volume=17, DOI=http://dx.doi.org/10.1016/0306-4379(92)90014-E, number=3, journal=Information Systems, author=Hohenstein, Uwe and Engels, Gregor, year=1992, pages=209–242 

@articleEngels_Lewerentz_Nagl_Schäfer_Schürr_1992, title=Building Integrated Software Development Environments, Part I: Tool Specification, volume=1, number=2, journal=ACM Transactions on Software Engineering and Methodology (TOSEM), author=Engels, Gregor and Lewerentz, Claus and Nagl, Manfred and Schäfer, Wilhelm and Schürr, Andy, year=1992, pages=135–167 

@articleEngels_Gogolla_Hohenstein_Hülsmann_Löhr-Richter_Saake_Ehrich_1992, title=Conceptual Modelling of Database Applications Using an Extended ER Model, volume=9, DOI=http://dx.doi.org/10.1016/0169-023X(92)90008-Y, number=2, journal=Data &; Knowledge Engineering, author=Engels, Gregor and Gogolla, Martin and Hohenstein, Uwe and Hülsmann, Klaus and Löhr-Richter, Perdita and Saake, Gunter and Ehrich, Hans-Dietrich, year=1992, pages=157–204 

@bookLöhr-Richter_Engels_1991, place=Leiden University, P.O. Box 9500, 2300 RA Leiden, The Netherlands, title=Incremental Design of Conceptual Database Schemata with CADDY, publisher=Leiden University, author=Löhr-Richter, Perdita and Engels, Gregor, year=1991 

@inproceedingsHohenstein_Engels_1990, title=Formal Semantics of an Entity-Relationship Query Language, booktitle=Proceedings of the 9th International Conference on Entity-Relationship Approach (ER 90), Lausanne, Switzerland, publisher=ER Institute, author=Hohenstein, Uwe and Engels, Gregor, year=1990, pages=177–188 

@inproceedingsEngels_1990, place=Berlin/Heidelberg, title=Elementary Actions on an Extended Entity-Relationship Database, volume=532, DOI=http://dx.doi.org/10.1007/BFb0017372, booktitle=Proceedings of the workshop on Graph Grammars and Their Application to Computer Science (1990), Bremen (Germany), publisher=Springer, author=Engels, Gregor, year=1990, pages=344–362 

@inproceedingsEbert_Engels_1989, place=Berlin/Heidelberg, series=Informatik-Fachberichte, title=Konzepte einer Software-Architektur-Beschreibungssprache, volume=212, booktitle=Software-Entwicklung: Konzepte, Erfahrungen, Perspektiven, Fachtagung, 1989, Marburg (Germany), publisher=Springer, author=Ebert, Jürgen and Engels, Gregor, year=1989, pages=238–250, collection=Informatik-Fachberichte 

@inproceedingsEngels_1989, title=CADDY-O: Syntaxgestütztes, graphisches Entwerfen konzeptioneller Datenbankschemata, volume=18, booktitle=Tagungsband GI-Fachtagung “Interaktive Schnittstellen für Informationssysteme”, TU Clausthal, Notizen zu Interaktive Systeme, author=Engels, Gregor, year=1989, pages=1–16 

@inproceedingsEngels_Hohenstein_Hülsmann_Löhr-Richter_Ehrich_1989, place=Berlin, title=CADDY: Computer-Aided Design of Non-Standard Databases, booktitle=Proceedings of the International Conference on System Development Environments &; Factories, Berlin, Germany, publisher=Pitman Publishing, author=Engels, Gregor and Hohenstein, Uwe and Hülsmann, Klaus and Löhr-Richter, Perdita and Ehrich, Hans-Dietrich, year=1989 

@bookEngels_1989, title=Benutzerschnittstelle und Architektur der integrierten Datenbankentwurfsumgebung CADDY (Kurzfassung), publisher=TU Braunschweig, author=Engels, Gregor, year=1989 

@bookEngels_Schäfer_1989, place=Stuttgart, title=Programmentwicklungsumgebungen: Konzepte und Realisierung, publisher=Teubner, author=Engels, Gregor and Schäfer, Wilhelm, year=1989 

@inproceedingsEngels_Janning_Schäfer_1988, place=New York, NY, USA, title=A Highly Integrated Tool Set for Program Development Support, DOI=http://dx.doi.org/10.1145/62453.62454, booktitle=Proceedings of the conference on ACM SIGSMALL/PC symposium on ACTES (SIGSMALL 1988), Cannes (France), publisher=ACM Press, author=Engels, Gregor and Janning, Thorsten and Schäfer, Wilhelm, year=1988, pages=1–10 

@inproceedingsEngels_Hohenstein_Neugebauer_Saake_Ehrich_1988, title=Konzeption einer integrierten Datenbank-Entwurfsumgebung, booktitle=Proceedings of DBTA/SI Data Dictionaries und Entwicklungswerkzeuge für Datenbank-Anwendungen, Zürich, Switzerland, publisher=Verlag der Fachvereine an den Schweiz. Hochschulen und Techniken, author=Engels, Gregor and Hohenstein, Uwe and Neugebauer, Leonore and Saake, Gunter and Ehrich, Hans-Dietrich, year=1988, pages=151–157 

@inproceedingsEngels_Hohenstein_Saake_Ehrich_1988, place=Darmstadt (Germany), title=Auf dem Weg zu einer integrierten Datenbank-Entwurfsumgebung, booktitle=Proceedings of the GI-Workshop on “Sprachspezifische Programmierumgebungen”, publisher=G. Snelting, author=Engels, Gregor and Hohenstein, Uwe and Saake, Gunter and Ehrich, Hans-Dietrich, editor=Engels, Gregor and Hohenstein, Uwe and Saake, Gunter and Ehrich, Hans-D.Editors, year=1988, pages=38–51 

@bookEbert_Engels_1988, title=Ein Konzept zur Beschreibung von Software-Architekturen, publisher=EWH Koblenz, author=Ebert, Jürgen and Engels, Gregor, year=1988 

@inproceedingsEngels_Janning_Schäfer_1988, title=Die Benutzerschnittstelle einer integrierten Modula-2 Programmentwicklungsumgebung, booktitle=Proceedings of GI-Workshop Sprachspezifische Programmierumgebungen, Darmstadt, Germany, author=Engels, Gregor and Janning, Thorsten and Schäfer, Wilhelm, year=1988 

@inproceedingsEngels_Schürr_1987, place=Berlin/Heidelberg, title=A Hybrid Interpreter in a Software Development Environment, volume=289, booktitle=Proceedings of the 1st European Software Engineering Conference (ESEC ’87), Strasbourg (France), publisher=Springer, author=Engels, Gregor and Schürr, Andy, year=1987, pages=80–88 

@inproceedingsEngels_Nagl_Schäfer_1987, title=On the Structure of Structure-Oriented Editors for Different Applications, volume=22, number=1, booktitle=Proceedings of the ACM SIGSOFT/SIGPLAN Software Engineering Symposium on Practical Software Development Environments, Palo Alto, USA, publisher=ACM SIGPLAN Notices, author=Engels, Gregor and Nagl, Manfred and Schäfer, Wilhelm, year=1987, pages=190–198 

@inproceedingsEngels_Lewerentz_Schäfer_1987, place=Berlin/Heidelberg, title=Graph Grammar Engineering: A Software Specification Method, volume=291, DOI=dx.doi.org/10.1007/3-540-18771-5, booktitle=Proceedings of the 3rd International Workshop on Graph-Grammars and Their Application to Computer Science, Warrenton, VA (USA), publisher=Springer, author=Engels, Gregor and Lewerentz, Claus and Schäfer, Wilhelm, year=1987, pages=186–201 

@inproceedingsEngels_Lewerentz_Nagl_Schäfer_1986, title=On the Structure of an Incremental and Integrated Software Development Environment, volume=2a, booktitle=Proceedings of the 19th Hawaii International Conference on System Sciences, Hawaii, USA, author=Engels, Gregor and Lewerentz, Claus and Nagl, Manfred and Schäfer, Wilhelm, year=1986, pages=585–597 

@inproceedingsEngels_Sandbrink_1986, place=Bautzen, title=Experiences with a Hybrid-Interpreter Based on Incremental Compilation Techniques, volume=12, booktitle=Proceedings of the Workshop on Compiler Compilers and Incremental Compilation Techniques, Bautzen, publisher=Berlin(Ost): Akademie der Wissenschaften der DDR, author=Engels, Gregor and Sandbrink, Andrea, year=1986, pages=172–184 

@bookEngels_1986, title=Graphen als zentrale Datenstrukturen in einer Software-Entwicklungsumgebung, author=Engels, Gregor, year=1986 

@inproceedingsEngels_Schäfer_1985, place=Berlin/Heidelberg, series=LNCS, title=Graph Grammar Engineering: A Method Used for the Development of an Integrated Programming Support Environment, volume=186, booktitle=Proceedings of the International Joint Conference on Theory and Practice of Software Development (TAPSOFT 1985), Berlin (Germany), publisher=Springer, author=Engels, Gregor and Schäfer, Wilhelm, year=1985, pages=179–193, collection=LNCS 

@inproceedingsEngels_Schäfer_1985, place=Florenz, title=The Design of an Adaptive and Portable Programming Support Environment, booktitle=Proceedings of the International Computing Symposium, Amsterdam (The Netherlands), author=Engels, Gregor and Schäfer, Wilhelm, year=1985 

@inproceedingsNagl_Engels_Gall_Schäfer_1983, place=Berlin/Heidelberg, series=LNCS, title=Software Specification by Graph Grammars, volume=153, DOI=dx.doi.org/10.1007/BFb0000113, booktitle=Proceedings of the 2nd International Workshop on Graph-Grammars and Their Application to Computer Science, Osnabrück (Germany), publisher=Springer, author=Nagl, Manfred and Engels, Gregor and Gall, Rupert and Schäfer, Wilhelm, year=1983, pages=267–287, collection=LNCS 

@articleEngels_Gall_Nagl_Schäfer_1983, title=Software Specification Using Graph Grammars, volume=31, DOI=http://dx.doi.org/10.1007/BF02251236, number=4, journal=Computing, author=Engels, Gregor and Gall, Rupert and Nagl, Manfred and Schäfer, Wilhelm, year=1983, pages=317–346 

@articleEngels_Pletat_Ehrich_1983, title=An Operational Semantics for Specifications of Abstract Data Types with Error Handling, volume=9, DOI=http://dx.doi.org/10.1007/BF00265557, number=3, journal=Acta Informatica, author=Engels, Gregor and Pletat, Udo and Ehrich, Hans-Dietrich, year=1983, pages=235–254 

@inproceedingsEngels_Schäfer_1982, place=München/Leipzig, title=Specification of a Programming Support Environment by Graph Grammars, booktitle=Proceedings of the conference on Graphtheoretic Concepts in Computer Science (WG), München (Germany), publisher=Hanser, author=Engels, Gregor and Schäfer, Wilhelm, year=1982, pages=47–62 

@inproceedingsPletat_Engels_Ehrich_1982, title=An Operational Approach to Conditional Algebraic Specifications, volume=82, booktitle=Proceedings of the 7eme Colloque sur les Arbres en Algebre et en Programmation, Lille (France), author=Pletat, Udo and Engels, Gregor and Ehrich, Hans-Dietrich, year=1982, pages=254–270 

@bookEngels_Pletat_Ehrich_1981, title=Handling Errors and Exceptions in the Algebraic Specifications of Data Types, publisher=University of Osnabrück, author=Engels, Gregor and Pletat, Udo and Ehrich, Hans-Dietrich, year=1981 

@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