Ebert, J., &; Engels, G. (1994). Observable or Invocable Behaviour - You Have to Choose. Vakgroep Informatica, Rijksuniversiteit Leiden.
LibreCat: /record/8193

Andries, M., &; Engels, G. (1994). Syntax and Semantics of Hybrid Database Languages. In Proceedings of the International Workshop on Graph Transformations in Computer Science (1993), Dagstuhl (Germany) (Vol. 776, pp. 19–36). Berlin/Heidelberg: Springer.http://dx.doi.org/10.1007/3-540-57787-4_2 
LibreCat: /record/8263
DOI: http://dx.doi.org/10.1007/3-540-57787-4_2

Engels, G., &; Groenewegen, L. (1994). Specification of coordinated behaviour by SOCCA. In Proceedings of the Third European Workshop on Software Process Technology (EWSPT 1994), Villard de Lans (France) (pp. 128–151). Berlin/Heidelberg: Springer.http://dx.doi.org/10.1007/3-540-57739-4_19 
LibreCat: /record/8264
DOI: http://dx.doi.org/10.1007/3-540-57739-4_19

Engels, G., &; Löhr, P. (1994). Visual Specification of Complex Database Actions. In Proceedings of the 2nd International East/West Database Workshop, Klagenfurt (Germany) (pp. 303–314). Berlin/Heidelberg: Springer.
LibreCat: /record/8265

Löhr-Richter, P., &; Engels, G. (1994). Visuelles Spezifizieren von komplexen Aktionen auf Datenbankstrukturen. GI-Datenbank Rundbrief, 13, 33–35.
LibreCat: /record/7407

Ebert, J., &; Engels, G. (1994). Design Representation. In Encyclopedia of Software Engineering (pp. 382–394). John Wiley &; Sons, Inc.
LibreCat: /record/7512

Engels, G., &; Groenewegen, L. (1994). SOCCA: Specifications of Coordinated and Cooperative Activities. In Software Process Modelling and Technology (pp. 71–102). Taunton: Research Studies Press.
LibreCat: /record/7513

Engels, G., &; Verrijn-Stuart, A. A. (1993). Integrationsaspekte bei verteilter Software-Entwicklung. In Fortschritt-Berichte VDI (pp. 45–53). VDI Verlag.
LibreCat: /record/7826

Andries, M., &; Engels, G. (1993). A Hybrid Query Language for the Extended Entity Relationship Model. Vakgroep Informatica, Rijksuniversiteit Leiden.
LibreCat: /record/8190

Ehrig, H., &; Engels, G. (1993). Towards a Module Concept for Graph Transformation Systems. Vakgroep Informatica, Rijksuniversiteit Leiden.
LibreCat: /record/8191