1. Baxter, R.J.: Exactly solved models in statistical mechanics. London: Academic Press 1982
2. Date, E., Jimbo, M., Kashiwara, M., Miwa, T.: Transformation groups for soliton equations: I. Proc. Jpn. Acad.57A, 342?347 (1981)
3. : II. Ibid.
4. : III. J. Phys. Soc. Jpn.50, 3806?3812 (1981)
5. IV. Physica 4D1982, 343?365