VISON: An Ontology-Based Approach for Software Visualization Tool Discoverability Leonel Merino ∗ , Ekaterina Kozlova †‡ , Oscar Nierstrasz ‡ , Daniel Weiskopf ∗ ∗ VISUS, University of Stuttgart, Germany † National Research University Higher School of Economics, Russia ‡ SCG, University of Bern, Switzerland