1. Fisher, M.E. and W. Selke, Phys. Rev. Lett. 44 (1980) 1502.
2. Elliott, R.J., Phys. Rev. 124 (1961) 346.
3. Hornreich, R.M., Luban, M., and S. Shtrikman, Phys. Rev. Lett. 35 (1975) 1678; Hornreich, R.M., J. Magn. Magn. Mater. 15–18 (1980) 387.
4. Redner, S. and H.E. Stanley, J. Phys. CIO (1977) 4765; Phys. Rev. B16 (1977) 4901.
5. Selke, W., Z. Physik B29 (1978) 133.