1. ABNT NBR 15751: Substation earthing systems - requirements (in portuguese);Brasileira de Normas Técnicas,2013
2. IEEE guide for safety in ac substation grounding;IEEE Std 80–2013 (Revision of IEEE Std 80–2000/ Incorporates IEEE Std 80-2013/Cor,2015
3. ABNT NBR 15749: Ground resistance and soil surface voltages measurements in earthing systems (in portuguese);Associeçāo Brasileira de Normas Técnicas,2009
4. IEEE guide for measuring earth resistivity, ground impedance, and earth surface potentials of a grounding system;IEEE Std 81–2012 (Revision of IEEE Std 81–1983),2012
5. Effect of the integration path on grounding measurements