1. Masuda, A., and Matsui, Y., Geochim. Cosmochim. Acta (to be published).
2. Masuda, A., Nature, 203, 1161 (1964).
3. Masuda, A., INSJ–65, Inst. Nucl. Study, Univ. Tokyo (1964).
4. Masuda, A., Chigaku-zasshi, 73, 139 (1964).
5. Masuda, A., and Matsui, Y., Jap. J. Geol. and Geo. (in the press).