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4. (4) P. L. Gallaschi: “Impulse and 60-cycle characteristics of a driven ground”, AIEE Trans., Vol. 60, pp. 123-128 (1941)
5. (5) R. Verma and D. Mukhedkar: “Impulse impedance of ground wire”, IEEE Trans., Vol. PAS-99, No. 5, pp. 2003-2007 (1980)