1. Ahrens, M., 2008. Lightning Fires and Lightning Strikes Report, NFPA Research and Statistics Department release, January 2005.
2. ANSI/IEEE 1100-2005, 2005. IEEE Recommended Practice for Powering and Grounding Electronic Equipment, IEEE Emerald Book.
3. Gomes, C., 2004. Interconnection of different earthing systems of a given installation. In: 27th International Conference on Lightning Protection (ICLP), Avignon, France, September 2004.
4. ZnO varistors with high voltage gradient and low leakage current by doping rare-earth oxide;He;Science in China Series E: Technological Sciences,2008
5. IEC 62305-1, 2006. Protection against Lightning – Part 1: General Principles.