1. Blumenthal, R.M., Getoor, R.K.: Markov Processes and Potential Theory. New York-London: Academic Press 1967
2. Brelot, M.: On Topologies and Boundaries in Potential Theory. Lectures Notes in Mathematics 175. Berlin-Heidelberg-New York: Springer 1971
3. Constantinescu, C, Cornea, A.: Examples in the Theory of Harmonic Spaces. Lecture Notes in Mathematics 69, 161?171. Berlin-Heidelberg-New York: Springer 1968
4. Constantinescu, C., Cornea, A.: Potential Theory on Harmonic Spaces. Berlin-Heidelberg-New York: Springer 1972
5. Fuglede, B.: Finely Harmonic Functions. Lecture Notes in Mathematics 289. Berlin-Heidelberg-New York: Springer 1972