1. Electrical Breakdown in Gases;Meek,1978
2. UHV Transmission Line Reference Book, California, USA, EPRI, 1982.
3. Weuhselspannungsmessungen mit Kugelfunkenstrecken auf reiluftversuchsfeldern;Peier;PTB-Mitteilungen,1977
4. The Influence of Dust on the A.C. Breakdown Voltage of a Rod Gap in Air;Schulz,1980
5. Effect of pollution on the Breakdown Voltage of Air;Al-Sayed;Proc.IEE,1978