1. J. Deny, Méthodes hilbertiennes en théorie du potentiel, pp. 122–201 in Potential Theory, Ed. M. Brelot, Stresa 1969, C.I.M.E., Edizioni Cremonese, Roma 1970.
2. M. Fukushima, Dirichlet forms and Markov processes, North-Holland/Kodansha, Amsterdam / Tokyo (1980)
3. Lecture Notes in Maths.;M.L. Silverstein,1974
4. Lecture Notes in Maths.;M.L. Silverstein,1976
5. M. Fukushima, these Proceedings.