M. Kolesik et L. Samaj, SERIES EXPANSION AND CAM STUDY OF THE NONUNIVERSAL BEHAVIOR OF THE SYMMETRICAL 16-VERTEX MODEL, Journal of statistical physics, 72(5-6), 1993, pp. 1203-1226
The phase diagram and the critical indices are investigated for the sy
mmetric 16-vertex model on the square lattice by combining a variation
al series expansion and the coherent anomaly method. The nonuniversal
critical exponents smoothly interpolate between two exactly solvable c
ases, namely the Baxter eight-vertex model and the Ising model.