1. Doob, J.: Conditional Brownian motion and the boundary limits of harmonic functions. Bull. Soc. math. France 85, 431?458 (1957).
2. Dvoretsky, A., and P. Erdös: Some problems on random walk in space. Proc. 2nd Berkeley Symposium on Math. Stat and Prob., 353?367. U. of California Press 1951.
3. Dynkin, E. B.: One-dimensional continuous strong Markov processes. Teor. Verojatn. Primen. 4, 1?52 (1959).
4. ItÔ, K., and H. P. McKean, Jr.: Diffusion (to appear).
5. Lévy, P.: Processus stochastiques et mouvement Brownien. Paris 1948.