1. Constantinescu B, Constantine F, Dusoiv F, Pascovici G (1996) Romania Rep Phys 48:31–38
2. UNSCEAR (1993) Exposure from natural sources of radiation. United Nation, New York
3. OECD (1979) Exposure to radiation from the natural radioactive building material, report by a group of experts of OECD. Nuclear Energy Agency, Paris
4. AL-Farrash AH, AL-Seikh AA, EL-Said AS (1997) Proceedings of the seventh International conference on environmental protection, Alexandria, Egypt, p 471
5. EL-Sayed AA, Aly HA, Abdel-Rasoul AA (1997) Proceedings of the seventh International conference on environmental protection, Alexandria, Egypt, p 646