1. Fluit, J. M., Friedman, L., van Eck, J., Snoek, and Kistemaker, Proc. Fifth Intern. Conf. Ionization Phenomena in Gases, Munich, 1961, 1, 131. Chaudri, R. M., Khan, Mustafa Yar, and Taseer, Abdul Latif, Nature, 177, 1226 (1956). Chaudhri, R. M., and Khan, Mustafa Yar, Proc. Fifth Intern. Conf. Ionization Phenomena in Gases. Munich, 1961, 2, 1195.
2. Frank, A. L., et al., ORNL-3114, UC-34-Phys. TID-4500 (seventeenth ed.) Rep., July 2, 1962. Emerson, L. C., et al., ORNL-3450, UC-34-Phys., TID-4500 (twentieth ed.), Rep., (July 30 1963).
3. Chaudhri, Rafi Mohammed, et al., Sixth Intern. Conf. Ionization Phenomena in Gases, Paris, July 8–13, 1963, 4, 5, 89.
4. McAlister, A. J., and Stern, E. A., Bull. Amer Phys. Soc., 8, 392 (1963).