1. See e.g. D. Pines, Ph. Nozières, The Theory of Quantum Liquids, vol 1, Benjamin, New York, 1966
2. L.D. Landau, E.M. Lifshitz, Statistical Physics, third ed., Pergamon, New York, 1980.
3. For a review see e.g. S. Das Sarma, A. Pinczuk (Eds.), Perspectives in Quantum Hall Effects, Wiley, New York, 1996.
4. What is the spin of a spin wave?
5. For a recent review see e.g. M.R. Norman, C. Pépin, Rep. Prog. Phys. 66 (2003) 1547.