1. Anderson, H., Fermi, E., von Grosse, A., Phys. Rev., 59, 52 (1941).
2. Grummitt, W. E., Gueron, J., Wilkinson, G., Yaffe, L., unpublished work (Montreal, 1944).
3. Elliott, L. G., unpublished work (Montreal, 1945).
4. Thode, H. G., Graham, R. L., Harkness, A. L., unpublished work (Hamilton, Ont., 1945).