1. M. Bilge, S. Özdemir Kart, H. H. Kart, and T. Cagin, J. Achiev. Mater. Manufact. Eng. 31, 29 (2008).
2. S. Patra, S. Mondal, and P. Mitra, J. Phys. Sci. 13, 229 (2009).
3. S. Liu, H. Zhang, and M. T. Swihart, Nanotechnology 20, 235603 (2009).
4. J. P. Borah and K. C. Sarma, Acta Physica Polonica A 114, 713 (2008).
5. M. Y. Nadeem and W. Ahmed, Turk. J. Phys. 24, 651 (2000).