1. A. O. Allen, Eadiation Res.1, 85 (1954).
2. T. J. Sworski, Radiation Res.6, 645 (1957).
3. J. W. Boyle, Radiation Res.17, 427, 450 (1962).
4. L. T. Bugaenko, Khuan Guan'-lin', and N. A. Bakh, Dokl. AN SSSR,149, 1099 (1963).
5. A. K. Pikaev, P. Ya. Glazunov, and V. I. Spitsyn, Dokl. AN SSSR,150, 1077 (1963).