Simmons, J. P., & Simmons, P. (1999). Soares book on grounding (7.).

Simmons, J. Philip, and Philip Simmons. Soares Book on Grounding. 7. Richardson, Texas : International Association of Electrical Inspectors, 1999.

Simmons, J. Philip, and Philip Simmons. Soares Book on Grounding. 7. 1999.