Vardakis, G. E. ., M. Danikas, and A. Nterekas. “Partial Discharges in Cavities and Their Connection With Dipoles, Space Charges, and Some Phenomena Below Inception Voltage”. Engineering, Technology & Applied Science Research, vol. 10, no. 4, Aug. 2020, pp. 5869-74, doi:10.48084/etasr.3593.