[1] Fraunhofer Institute for Experimental Software Engineering, Fraunhofer-Platz 1, Kaiserslautern
[2] University of Oulu, Department of Information Processing Science, Oulu
[3] University of Southern Denmark, The Maersk Mc-Kinney Møller Institute, Campusvej 55, Odense
[4] University of Helsinki, Department of Computer Science, Helsinki
[5] Aalto University, Department of Computer Science and Engineering, Aalto