1. ANSI/IEEE Std.80. IEEE guide for safety in AC substation grounding, New York; 2000.
2. Progress in step and touch voltage equations of ANSI/IEEE Std.80;Sverak;IEEE Trans Power Delivery,1999
3. Problems encountered with the APM of analyzing grounding systems;Garret;IEEE Trans Power Delivery,1985
4. The finite element method;Hughes,1987
5. Boundary element techniques;Brebbia,1984