1. A. P. Young, these lectures (1983).
2. D. Sherrington and S. Kirkpatrick, Phys. Rev. Lett. 35, 1792 (1975)
3. A. B. Harris, T. C. Lubensky and J.H. Chen, Phys. Rev. Lett. 38, 415 (1976)
4. J. H. Chen and T. C. Lubensky, Phy. Rev. B16, 2106 (1976)
5. A. J. Bray and S. A. Roberts, J. Phys. C13, 5405 (1980)