Tool integration by models, not only by metamodels applying modeling to tool integration

Integration of tools that support different models defined by different metamodels cannot be achieved by integrating or merging the metamodels of the different models, or by making a minimum, common metamodel for these models. However, it can be achieved by making common representatives of the various models and model elements maintained by the tools. This paper has investigated several existing model/metamodel integration approaches, and described an approach where tool integration works by models, not only by metamodels.