1. High Voltage Measurement Techniques;Schwab,1972
2. Elektrizitätszähler und Messwandler;Betz,1959
3. Entwicklungstendenzen im Wandlerbau;Hermstein;Elektrizitatswirtschaft,1969
4. Electrical Machines;Draper,1976
5. IEC Publication 52 (1960). Recommendations for Voltage Measurements by Means of Sphere-gaps (one sphere earthed).