1. Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz
1, 76344 Eggenstein-Leopoldshafen, Germany
2. Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
3. Institute of Mathematics, Physics and Mechanics & Faculty of Civil and Geodetic Engineering, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia