1. E. Ising, Zeitschrift für Physik 21, 253 (1925).
2. S. G. Brush, Rev. Mod. Phys. 39, 883 (1967).
3. G. Mussardo, Statistical Field Theory: An Introduction to Exactly Solved Models in Statistical Physics, Oxford Graduate Texts (Oxford Univ. Press, New York, 2010).
4. R. J. Baxter, Exactly Solved Models in Statistical Mechanics (Academic, New York, 1982).
5. H. A. Kramers and G. H. Wannier, Phys. Rev. 60, 252 (1941).