1. Dolgopolov, V. V., El-Siragy, N. M., and Sayed, Y. A. (1975). In7th European Conference on Controlled Fusion and Plasma Physics, Lausanne.
2. El-Siragy, N. M., Khalil, Sh. M., Amein, W. H., and Nagy, O. Z. (1984).Egyptian Journal of Physics,15, 213.
3. Khalil, Sh. M., El-Siragy, N. M., Sayed, Y. A., and El-Sherif, R. N. (1984).Physica Scripta,30, 357.