1. Bryant, F. J., Morgan, A., and Spicer, G. S., AERE R 3030 (Harwell, 1959).
2. Löw, K., and Edvarson, K., Nature, 183, 1104 (1959).
3. Lillegraven, A., FFIF Rapport F-378 (April 1959).
4. Vuorinen, A. P. U., Rev. Sci. Instr., 31, 573 (1960).
5. Strontium-90 in Milk and Agricultural Materials in the United Kingdom in 1958–59. Agricultural Research Council, Radiobiological Laboratory, Report No. 2 (1960).