1. A. Abraham,The Principles of Nuclear Magnetism, Clarendon, Oxford (1961).
2. S. V. TyablikovMethods in the Quantum Theory of Magnetism, Nauka, Moscow (1975) English version: Plenum, New York (1967).
3. D. N. Zubarev and Yu. G. Rudoy,Phys. Usp.,163, 188–191 (1993).
4. M. Fisher,The Nature of the Critical Point (Lecture in Theoretical Physics), Colorado Univ., Colorado (1965).
5. P. Resibois and M. De Leener,Phys. Rev.,152, 305 (1966).