1. Yu. A. Kazanskii and E. S. Matusevich, Bulletin of the Information Center for Nuclear Data [in Russian], Vol. 4, Atomizdat, Moscow (1967).
2. V. K. Daruga et al., At. Énerg.,26, 80 (1969).
3. F. Brooks, Nucl. Instrum. and Methods,4, 240 (1959); V. A. Dulin, Yu. A. Kazanskii, and I. V. Shugar, At. Énerg.,14, 488 (1963).
4. D. Beard and A. McLellan, Phys. Rev.,140B, 888 (1965).
5. E. S. Matusevich, At. Énerg.,20, 51 (1966).