1. Siegbahn, Kai, Ark. Mat, Ast. o. Fysik, 30, A, No. 20 (1944).
2. Siegbahn, Kai and Bohr, E., Ark. Mat., Ast. o. Fysik, 30, A, No. 3 (1943).
3. Siegbahn, Kai and SlÃtis, H., Ark. Mat., Ast. o. Fysik, 32, A, No. 9 (1945).
4. Richardson, J. R., Phys. Rev., 55, 609 (1939). Lyman, E. M., Phys. Rev., 55, 234, 1123 (1939). Watase and Itoh ., Proc. Phys.-Math. Soc. Japan, (3), 21, 389 (1939).
5. Hudson, C, Herb, K., and Plain, G., Phys. Rev., 57, 587 (1940). Valley, G., Phys. Rev., 56, 838 (1939).