Ehrig, Hartmut, Reiko Heckel, Mercé Llabrés, and Fernando Orejas. Basic Properties of Double Pullback Graph Transitions. Technical University of Berlin, 1999.
LibreCat: /record/8203

Engels, Gregor, Roland Hücking, Stefan Sauer, and Annika Wagner. UML Collaboration Diagrams and Their Transformation to Java. University of Paderborn, Department of Computer Science, 1999.
LibreCat: /record/8204

Engels, Gregor, Pieter Jan t’Hoen, Ray Dassen, Luuk Groenewegen, Ida G. Sprinkhuizen-Kuyper, and Pieter Koopman. SOCCA Extended with UML like Packages. Leiden Institute of Advanced Computer Science, 1999.
LibreCat: /record/8205

Engels, Gregor, Ray Dassen, Luuk Groenewegen, Ida G. Sprinkhuizen-Kuyper, Pieter Koopman, and Pieter Jan t’Hoen. A Formalisation of SOCCA Using Z, Part 1: The Type Level Concepts. Leiden Institute of Advanced Computer Science, 1999.
LibreCat: /record/8206

Sauer, Stefan, and Gregor Engels. “UML-Basierte Modellierung von Multimediaanwendungen.” In Modellierung 1999, Workshop Der Gesellschaft Für Informatik e. V. (GI), März 1999 in Karlsruhe, 155–70. Karlsruhe, Germany: Teubner, Stuttgart, 1999.
LibreCat: /record/8321

Sauer, Stefan, and Gregor Engels. “OMMMA: An Object-Oriented Approach for Modeling Multimedia Information Systems.” In Proceedings of the Workshop on Multimedia Information Systems (MIS 1999), Indian Wells, CA (USA), 64–71. Indian Wells, California, USA, 1999.
LibreCat: /record/8322

Corradini, Andrea, Martin Große-Rhode, and Reiko Heckel. “An Algebra of Graph Derivations Using Finite (Co-) Limit Double Theories.”http://dx.doi.org/10.1007/3-540-48483-3_7__In Selected Papers of the 13th International Workshop on Recent Trends in Algebraic Development Techniques (WADT 1998), Lisbon (Portugal), 1589:92–106. LNCS. Berlin/Heidelberg: Springer, 1999.http://dx.doi.org/10.1007/3-540-48483-3_7 .
LibreCat: /record/8323
DOI: http://dx.doi.org/10.1007/3-540-48483-3_7

Corradini, Andrea, Reiko Heckel, and Ugo Montanari. “From SOS Specifications to Structured Coalgebras: How to Make Bisimulation a Congruence.”http://dx.doi.org/10.1016/S1571-0661(05)80273-7__In Proceedings of the 2nd Workshop on Coalgebraic Methods in Computer Science (CMCS 99), 19:118–41. Electronic Notes in TCS. Amsterdam, The Netherlands: Elsevier, 1999.http://dx.doi.org/10.1016/S1571-0661(05)80273-7 .
LibreCat: /record/8324
DOI: http://dx.doi.org/10.1016/S1571-0661(05)80273-7

Engels, Gregor, Reiko Heckel, and Stefan Sauer. “Dynamic Meta Modelling: A Graphical Approach to Operational Semantics.” In Proceedings of the Workshop on Rigorous Modeling and Analysis with the UML: Challenges and Limitations (Satellite Event of the Conference on Onject-Oriented Programming, Systems, Languages, and Applications (OOPSLA 1999)), Denver, CO (USA), 1999.
LibreCat: /record/8325

Engels, Gregor, and Stefan Sauer. “MVC-Based Modeling Support for Embedded Real-Time Systems.” In Proceedings of OMER Workshop, Herrsching, Germany, 11–14. Herrsching, Universität der Bundeswehr München, Fakultät für Informatik, 1999.
LibreCat: /record/8326