1. L. Landau, I. Lifshitz, Statistical Physics, Pergamon (1958) chap. 14
2. The spin wave modes in a sphere have been calculated by L. R. Walker, Phys. Rev. 105, 390 (1957)
3. For a simple presentation ferromagnetic domains, see C. Kittel Introduction to Solid State Physics, 3d ed. Wiley 1966, Chap. 15
4. See for instance P. G. de Gennes, Superconductivity of metals and alloys, Benjamin, 1965
5. See for instance P. G. de Gennes, The Physics of Liquid Crystals, Oxford, 1974