1. N. I. Alekseev, Zh. Tekh. Fiz. 74(8), 45 (2004) [Tech. Phys. 49 (8), 998 (2004)].
2. N. I. Alekseev, Fiz. Tverd. Tela (St. Petersburg) 48(8), 1518 (2006) [Phys. Solid State 48 (8), 1605 (2006)].
3. N. I. Alekseev, Fiz. Tverd. Tela (St. Petersburg) 48(8), 1527 (2006) [Phys. Solid State 48 (8), 1616 (2006)].
4. S. Sato, A. Kawabata, D. Kondo, M. Nihei, and Y. Awano, Chem. Phys. Lett. 402, 149 (2005).
5. A. Okamoto and H. Shinohara, Carbon 43, 431 (2005).