1. UNSCEAR (2000) Sources and effects of ionizing radiation. United Nations Scientific Committee on the Effect of Atomic Radiation, United Nations, New York.
2. UNSCEAR (1993) Ionizing Radiation Sources and Effects on Ionizing Radiation. United Nations Scientific Committee on the Effects of Atomic Radiation, United Nations, New York.
3. More than forty years of studies of natural radioactivity in Brazil;AS Paschoa;Technol,2000
4. Bennett BG (1997) Exposure to natural radiation worldwide. In: Proceedings of the Fourth International Conference on High Levels of Natural Radiation: Radiation Doses and Health Effects. Beijing, China. Elsevier, Tokyo. 15–23.
5. An introductory overview of the epidemiological study on the population at the high background radiation areas in Yangjiang, China;L Wei;J Radiat Res,2000