D. R. Nelson and L. Peliti, J. Phys. France, vol.48, p.1085, 1987.

Y. Kantor and D. R. Nelson, Phys. Rev. Lett, vol.58, p.4020, 1987.

M. Paczuski, M. Kardar, and D. R. Nelson, Phys. Rev. Lett, vol.60, p.2638, 1988.

F. David and E. Guitter, Europhys. Lett, vol.5, p.709, 1988.

M. Baig, D. Espriu, and J. Wheater, Nucl. Phys, vol.314, p.587, 1989.

R. Renken and J. Kogut, Nucl. Phys, vol.342, p.753, 1990.

R. Harnish and J. Wheater, Nucl. Phys, vol.350, p.861, 1991.

Y. Kantor and M. V. Jari´cjari´c, Europhys. Lett, vol.11, p.157, 1990.

P. , D. Francesco, and E. Guitter, Europhys. Lett, vol.26, p.455, 1994.

R. J. Baxter and S. K. Tsang, J. Phys. A13 Math. Gen, p.1023, 1980.

R. J. Baxter, J. Phys. A19 Math. Gen, vol.11, p.2821, 1970.