1. Huang, K. Statistical Mechanics. (Wiley, New York, 1987).
2. Wen, X. G. Quantum Field Theory of Many-body Systems: From The Origin of Sound To An Origin of Light and Electrons. (Oxford University Press, Oxford, 2004).
3. Sethna, J. P. Statistical Mechanics: Entropy, Order Parameters and Complexity. (Oxford University Press, New York, 2006).
4. Sachdev, S. Quantum Phase Transitions. (Cambridge University Press, Cambridge, 1999).
5. Dicke, R. H. Coherence in spontaneous radiation processes. Phys. Rev. 93, 99–110 (1954).