REFERENCES
- Barry A. Cipra, An introduction to the Ising model, American Mathematical Monthly, 94 (1987) 937–959.
- K. O. Friedrichs, The identity of weak and strong extensions of differential operators. Trans. AMS, 55 (1944) 132–151.
- M. Kac, Statistical Independence in Probability Analysis and Number Theory, Carus Monograph, MAA, 1959.