1. Natural radioactivity of the soil samples;Sohrabi,1997
2. Assessment of risks from combined exposure to radiation and other agents at environmental levels;Jung,1997
3. United Nations Scientific Committee on the Effects of atomic Radiation, Sources and effects of ionizing radiation, 1993.
4. NRPB, Health risks for radon, Environmental Radon Newsletter, Issue 25, 2000.
5. Very high background radiation areas (VHBRAs) of Ramsar: do we need any regulations to protect the inhabitants?;Mortazavi,2001