Onyszkiewicz, Z. - In: Physica A: Statistical Mechanics and its Applications 103 (1980) 1, pp. 274-294
A special case of the spin system proposed in the previous paper (i.e. the first paper of this series) is considered, which includes the Heisenberg term besides the four-spin coupling. By means of an improved renormalization within the high density expansion method, the formulas for the...