International Collaboration Research Project on Geometric Computing, Bonn & Karlsruhe, Germany, Universität Bonn & Karlsruhe Institute of Technology (2010/06–2010/06)
International Collaboration Research Project on Geometric Computing, Bonn, Germany, Universität Bonn (2009/06–2009/07)
Joint Research Collaboration, Karlsruhe, Germany, Universität Karlsruhe (2009/05–2009/05)
International Collaboration on Joint Research in Graph Algorithms, Karlsruhe, Germany, Universität Karlsruhe (TH) (2009/05–2009/06)
Joint Research Collaboration, Bonn, Germany, Universität Bonn (2009/06–2009/07)
