1. Wimmics, Université Côte d’Azur, Inria, CNRS, I3S, Sophia Antipolis, France. E-mail: fabien.gandon@inria.fr
2. CDL-Flex, Vienna University of Technology, Austria. E-mail: marta.sabou@ifs.tuwien.ac.at
3. FIZ Karlsruhe, Leibniz Institute for Information Infrastructure, KIT Karlsruhe, Germany. E-mail: Harald.Sack@fiz-Karlsruhe.de