1. A Y Kitaev, Ann. Phys., 303, (2003) 2.
2. L Balents, Nature, 404, (2010) 199.
3. Z Y Meng, et.al., Nature, 88, (2010) 487.
4. P Fazekas, “Magnetism and electron correlations in strongly correlated systems,” Word scientific (2010).
5. B K Clark, D A Abanin and S L Sondhi, Phys. Rev. Lett., 107, (2011) 087204.
6. A Mattsson., P Frojdh, and T Einarsson, Eur. Phys. J. B, 49, (1994) 3997.
7. H Mosadeq, F Shahbazi and S A Jafari, J. Phys. Cond. Mat., 23, (2011) 226006.
8. A Mulder, R Ganesh, L Capriotti, and A Paramekanti, Phys. Rev. B, 81, (2010) 214419.
9. H Y Yang., New J. Phys., 14, (2012) 115027.
10. T Holstein and H Primakoff, Phys. Rev., 58, (1940) 1098.