1. UNSCEAR, 1962. p. 389.
2. Ayad M. The atomic radiation-risks, medical and technical aspects. Methods of protection and therapy. Saudi Arabia, 1992. p. 55, 77.
3. IAEA. Population-dose evaluation and standards from man and his environment (STI/PUB/355). Proceedings of International Atomic Energy, Vienna, 1974. p. 369, 395.
4. Exposure of man to ionizing radiation arising from medical procedures;Phys Med. Biol.,1957
5. Anon. ICRP Publication 26, 1977. p. 35.