1. C. W. Gardiner, Handbook of stochastic methods, Springer Berlin, 1985.
2. H. Haken, New York: Springer-Verlag, 1983.
3. P. A. P. Moran, An introduction to probability theory. (1968).
4. H. Risken, in The Fokker-Planck Equation (Springer, 1996), pp. 63-95.