1. Brown, K. L., Eldredge, A. L., Helm, R. H., Jasberg, J. H., Lebacqz, J. V., Loew, G. A., Mozley, R. F., Neal, R. B., Panofsky, W. K. H., and Turner, T. F., Proc. Intern. Conf. High Energy Accelerators, 85 (1961).
2. Nygard, J. C., and Post, R. F., Nuclear Instr. and Methods, 2, No. 1, 126 (1961).
3. Crowley-Milling, M. C., Jarvis, T. R., Miller, C. W., and Saxon, G., Nature, 191, 483 (1961).
4. Saxon, G., Jarvis, T. R., and White, I., Proc. Inst. Elec. Eng., 110, No. 8, 1365 (1963).
5. Bell, M., Bramham, P., and Montague, B. W., Nature, 198, 277 (1963).