1. (1) Les Renardières Group : “Double impulse tests of long airgaps”, IEE Proc., Vol. 133, Pt. A, No. 7, pp. 395-483 (1986)
2. (2) I. Gallimberti, J. Hepworth, and R. Klewe : “Spectroscopic investigation of impulse corona discharges”, J. Phys. D: Appl., Phys., Vol. 7, pp. 880-898 (1974)
3. (3) The Visualization Society of Japan : Optical Visualization Methods, Asakura Shoten, Tokyo (1998) (in Japanese)
4. (4) K. Muraoka and M. Maeda : Applied Laser Diagnostics of Plasmas and Gases, Sangyo Tosho, Tokyo (1995) (in Japanese)
5. (5) Les Renardières Group : “Negative discharges in log air gaps at les Renardières”, Electra, Vol. 74, pp. 67-216 (1981)