1. M. M. Komochkov and V. N. Mekhedov, Atomnaya Énergiya4, 71 (1958).
2. N. G. Gusev, Handbook of Radioactive Radiations [in Russian] (MEDGIZ. 1955).
3. V. I. Baranov, Radiometry [in Russian] (Izd AN SSSR, 1955).
4. S. Zech, Czechoslovak Fiz. J.7, 33 (1957).