Samuel Sheet, S. “The Effect of Lightning Impulse and Switching (over Voltages) on Stress Distribution and Space Charge Accumulation of HVDC XLPE Cables at Load and No Load”. Al-Rafidain Engineering Journal (AREJ), vol. 16, no. 3, July 2008, pp. 50-61, doi:10.33899/rengj.2008.44628.