UNSCEAR, “Sources, Effects and Risks of Ionization Radiation”, United Nations Scientific Committee on the Effects of Atomic Radiation, Report to the General Assembly, with Annexes, New York, 2000.
 M. B. Radenkovic, S. M. Alshikh, V. B. Andric and S. S. Miljanic, “Radioactivity of Sand from Several Renowned Public Beaches and Assessment of the Corresponding Environmental Risks,” Journal of the Serbian Chemical Society, Vol. 74, No. 4, 2009, pp. 461-470. doi:10.2298/JSC0904461R
 A. S. Alaamer, “Assessment of Human Exposures to Natural Sources of Radiation in Soil of Riyadh, Saudi Arabia,” Turkish Journal of Engineering & Environmental Sciences, Vol. 32, 2008, pp. 229-234.
 K. A. Kabir, S. M. Islam and M. Rahman, “Distribution of Radionuclides in Surface Soil and Bottom Sediment in the District of Jessori, Bangladesh and Evaluation of Radiation Hazard,” Journal of Bangladesh Academy of Sciences, Vol. 33, No. 1, 2009, pp. 117-130.
 E. B. Faweya and A. I. Babalola, “Radiological Safety Assessment and Occurrence of Heavy Metals in Soil from Designated Waste Dumpsites Used for Building and Composting in Southwestern Nigeria,” The Arabian Journal for Science and Engineering, Vol. 35, No. 2, 2010, p. 220.
 N. N. Jibiri and G. O. Adewuyi, “Radionuclide Contents and Physico-Chemical Characterization of Solid Waste and Effluent Samples of Some Selected Industries in the City of Lagos, Nigeria,” Radioprotection, Vol. 43, No. 2, 2008, pp. 203-212. doi:10.1051/radiopro:2007053
 N. Akhtar, M. Tufail, M. A. Choudhry, S. D. Orfi and M. Waqas, “Radiation Dose from Natural and Manmade Radionuclides in the Soil of Niab, Faisalabad, Pakistan,” The Nucleus, Vol. 41, No. 1-4, 2004, pp. 27-34.
 S. Hafezi, J. Amidi and A. Attarilar, “Concentration of Natural Radionuclides in Soil and Assessment of External Exposure to the Public in Tehran, Iran,” Journal of Rabdiation Research, Vol. 3, No. 2, 2005, pp. 85-88.
 S. Singh, A. Rani and R. Mahajan, “226Ra, 232Th and 40K Analysis in Soil Samples from Some Areas of Punjab and Himachal Pradesh, India Using Gamma Ray Spectrometry,” Radiation Measurements, Vol. 39, No. 4, 2005, pp. 431-439. doi:10.1016/j.radmeas.2004.09.003
 H. Florou, G. Trabidou and G. Nicolaou, “An Assessment of the External Radiological Impact in Areas of Greece with Elevated Natural Radioactivity,” Journal of Environmental Radioactivity, Vol. 93, No. 2, 2007, pp. 74-83. doi:10.1016/j.jenvrad.2006.11.009
 A. Bozkurt, N. Yorulmaz, E. Kam, G. Karahan and A. Osmanlioglu, “Assessment of Environmental Radioactivity for Sanliurfa Region of Southeastern Turkey,” Radiation Measurements, Vol. 42, No. 8, 2007, pp. 1387-1391. doi:10.1016/j.radmeas.2007.05.052
 K. M. Dabayneh, L. A. Mashal and F. I. Hasan, “Radio-activity Concentration in Soil Samples in the Southern Part of the West Bank, Palestine,” Radiation Protection Dosimetry, Vol. 131, No. 2, 2008, pp. 265-271. doi:10.1093/rpd/ncn161
 G. Shanthi, J. Kumaran, G. Allen Raj and C. Maniyan, “Measurement of Activity Concentration of Natural Ra- dionuclides for the Assessment of Radiological Indices,” Radiation Protection Dosimetry, Vol. 141, No. 1, 2010, pp. 90-96. doi:10.1093/rpd/ncq142
 I. Okeyode and A. Oluseye, “Studies of the Terrestrial Outdoor Gamma Dose Rate Levels in Ogun-Osun River Basins Development Authority Headquarters, Abeokuta, Nigeria,” Physics International, Vol. 1, No. 1, 2010, pp. 1-8. doi:10.3844/pisp.2010.1.8
 R. Ramola1, V. Choubey, G. Prasad, G. Gusain, Z. Tosheva and A. Kies, “Radionuclide Analysis in the Soil of Kumaun Himalaya, India, Using Gamma Ray Spectrometry,” Current Science, Vol. 100, No. 6, 2011, pp. 906-914.
 R. Mehra, S. Kumar, R. Sonkawade, N. Singh and K. Badhan, “Analysis of Terrestrial Naturally Occurring Radionuclides in Soil Samples from Some Areas of Sirsa district of Haryana, India Using Gamma Ray Spectrometry,” Environmental Earth Sciences, Vol. 59, No. 5, 2009, pp. 1159-1164. doi:10.1007/s12665-009-0108-3
 M. Uosif, “Gamma-Ray Spectroscopic Analysis of Selected Samples from the Nile River Sediments in Upper Egypt,” Radiation Protection Dosimetry, Vol. 123, No. 2, 2007, pp. 215-220. doi:10.1093/rpd/ncl103
 N. Huy and T. Luyen, “Study of External Exposure Doses from Terrestrial Radioactivity in Southern Vietnam,” Radiation Protection Dosimetry, Vol. 118, No. 3, 2005, pp. 331-336. doi:10.1093/rpd/nci341
 J. Beretka and P. Mathew, “Natural Radioactivity of Australian Building Materials, Industrial Wastes and by Products,” Health Physics, Vol. 48, No. 1, 1995, pp. 87-95. doi:10.1097/00004032-198501000-00007
 V. Ramasamy, S. Senthil, V. Meenakshisundaram and V. Gajendran, “Measurement of Natural Radioactivity in Beach Sediments from North East Coast of Tamilnadu, India,” Research Journal of Applied Sciences, Engineering and Technology, Vol. 1, No. 2, 2009, pp. 54-58.
 V. Ramasamy, G. Suresh, V. Meenakshisundaram and V. Gajendran, “Evaluation of Natural Radionuclide Content in River Sediments and Excess Lifetime Cancer Risk Due to Gamma Radioactivity,” Research Journal of Environmental and Earth Sciences, Vol. 1, No. 1, 2009, pp. 6-10.
 H. Taskin, M. Karavus, P. Ay, A. Topuzoglu, S. Hindiroglu and G. Karahan, “Radionuclide Concentrations in Soil and Lifetime Cancer Risk Due to the Gamma Radioactivity in Kirklareli, Turkey,” Journal of Environmental Radioactivity, Vol. 100, No. 1, 2009, pp. 49-53. doi:10.1016/j.jenvrad.2008.10.012