1. H Lemarchand and G Nicolis,J. Stat. Phys. 37, 609 (1984)
2. W Horsthemke and R Lefever inNoise in nonlinear dynamical systems, edited by F Moss and P V E McClintock (Cambridge, University Press, 1989)
3. B J West and K Lindenberg, inSimple models of equilibrium and nonequilibrium phenomena, edited by J L Lebowitz (Elsevier, New York, 1987)
4. K Ito and H P McKean,Diffusion processes and their sample paths (Academic, New York, 1965)
5. I I Gikhman and A V Skorohod,Stochastic differential equations (Springer-Verlag, Berlin, 1972)