1. Department of Geophysics
2. The Nanotechnology and Graphene Research Center (PRINTG)
3. Universitas Padjadjaran
4. Jatinangor
5. Indonesia
6. Clausthal University of Technology
7. Institute of Applied Mechanics
8. Clausthal Zellerfeld 38678
9. Germany
10. Physics Department and Research Center OPTIMAS
11. University of Kaiserslautern
12. 67663 Kaiserslautern