1. University Politehnica of Bucharest, Splaiul Independentei, 313, Bucharest, Romania
2. University Politehnica of Bucharest, Bucharest, Romania
3. Széchenyi István University, Egyetem tér 1., Hungary
4. Széchenyi István University, Gyõr, Egyetem tér 1., 9026 Hungary
5. University of Iceland, School of Engineering and Natural Sciences—Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, VR-2/V02-237, Reykjavik, Iceland