1. Decree of Ministries of Health and the Chemical Industry of March 21, 1963, on health protection against ionizing radiation and on managing the sources of ionizing radiation. Sb. z., part 19, 25. 4. (1963).
2. Report of the United Nations Scientific Committee on the Effects of Atomic Radiation, General Assembly Official Records, No. 17 (A/3838), New York (1958), 54.
3. Report of Committee II on Permissible Dose for Internal Radiation (1959), Health Phys.3 (1960), 1.
4. Read J., Mottram J.: Brit. J. Radiol.,22 (1939), 54.
5. Hultquist B.: Studies on Naturally Occurring Ionizing Radiations, Kungl. Svenska Vetenskapsakad. Handl.,6 (1956), 5.