1. P Hu, L H Xie and P Huang, Physica B339, 74 (2003)
2. W L Yu, J. Chem. Phys. 59, 261 (1998)
3. W C Zheng, S Tang and X X Wu, Physica B348, 42 (2004)
4. W L Feng, Pramana — J. Phys. 70, 705 (2008)
5. M G Brik, C N Avram and N M Avram, Physica B384, 78 (2003)