Gao, X.G., Zhou, Y.S. and Wang, Y.F. (2012) Research On the Burial Depths Characteristics of the Annular Grounding Electrodes in UHVDC Converter Stations. Insulators and Surge Arresters, 2, 72-76.
 Chen, L., Wang, H.J. and Wan, Y.L. (2012) Online Monitoring and Communication of High Voltage Electrode Based on GPRS. Industrial Control Computer, 81-82.
 Zhu, Z.X., Han, Y. and Hui, N. (2012) Application and Development of Ground Elec-trode Materials for HVDC Transmission System. East China Electric Power, 40, 265-269.
 Yu, Y., Wei, C. and Zhu, L. (2010) Impact of HVDC ground Electrode Current on Transformers with Different Structures. Power System Protection and Control, 38, 71-76.
 Yang, Y.M., Liu, X.M. and Chen, T. (2012) Impact of Soil Structure Adjacent to Ground Electrodes of UHVDC Power Transmission Lines on DC Bias of Power Transformers. Power System Technology, 36, 26-32.
 Yang, W.Y., Liu, J. and Wang, J.Y. (2006) On-Line Monitoring System for HVDC System Earth Pole. High Voltage Engineering, 32, 15-17.
 Lu, J.M., Xiao, D. and Mao, C.X. (2006) Analysis of Effects of DC Earthed Pole on Earth Surface Potential Distributions. High Voltage Engineering, 32, 55-58.
 Sima, W.X., Luo, L. and Yuan, T. (2012) Temperature Characteristic of Soil Resistivity and Its Effect on the DC Grounding Electrode Heating. High Voltage Engineering, 38, 1192-1198.
 Liu, Z.Y. (2009) UHVDC Transmission Theory. China Electric Power Press, Beijing.