1. Ahnstörm, G., and v. Ehrenstein, G., Acta Chem. Scand., 13, 855 (1959).
2. Westermark, T., Risö Report No.16; papers presented at the First Nordic Meeting on Food Preservation by Ionizing Radiations, Risö, April 25–26, 1960.
3. Kallman, H., Furst, M., and Brown, F., Nucleonics, 4, 48 (1956).
4. Pringsheim, P., “Fluorescence and Phosphorescence” (Intersci. Pub., Inc., New York, 1949).
5. Daniels, F., “Nuclear Geology”, edit. by Faul, H., chapter 6, 3 (Wiley and Sons, Inc., New York, 1957).