1. IEC‘Insulation co-ordination. Part 1. Definitions, principles and rules’, IEC 71-1, 1993
2. IEC‘Insulation co-ordination. Part 2. Application guides’, IEC 71-2, 1996
3. ‘Substation voltage upgrading’, EPRI report, EL-6474, 1989
4. Lightning protection of distribution lines