1. Neher, H. V., Science, 125, 1088 (1957).
2. Solon, L. R., Lowder, W. M., Zila, A. V., Levine, H. D., Blatz, H., and Eisenbud, M., Science, 127, 1183 (1958).
3. Solon, L. R., Lowder, W. M., Shambon, A., and Blatz, H., US Atomic Energy Comm. Health and Safety Lab. Report, No. 73 (November 1959).
4. Hultqvist, B., Kingl. Svenska Vetenskapsakademiens Hadlingar, 6, No. 3 (1956).
5. Beck, H. L., Condon, W. J., and Lowder, W. M., US Atomic Energy Comm. Health and Safety Lab. Report, No. 145 (April, 1964).