1. Á. Kiss, E. Koltay, S. Szalay, ATOMKI Közl.,8, 17, 1966 (in Hungarian).
2. A. Kiss, E. Koltay andA. Szalay, Nucl. Instr. and Meth.,46, 130, 1967.
3. R. Chick andF. J. Miranda, J. Sci. Instr.,29, 340, 1952.
4. B. Millar, British J. Appl. Phys.,6, 13, 1955.
5. J. M. Meek andJ. D. Craggs, Electrical Breakdown of Gases, Clarendon Press, Oxford, 1953.