R. Veiga, N. Sanches, R. M. Anjos, K. Macario, J. Bastos, M. Iguatemy, J. G. Aguiar, A. M. A. Santos, B. Mosquera, C. Carvalho, M. Baptista Filho and N. K. Umisedo, “Measurement of Natural Radioactivity in Brazilian Beach Sands,” Radiation Measurements, Vol. 41, No. 2, 2006, pp. 189-196. doi:10.1016/j.radmeas.2005.05.001
 United Nations Scientific Committee on the Effects of Atomic Radiation, “Sources and Effects of Ionizing Radiation,” Report to General Assembly, with Scientific Annexes, United Nations, New York, 2000.
 M. Ghiassi-nejad, S. M. J. Mortazavi, J. R. Cameron, A. Niroomand-rad and P. A. Karam, “Very High Background Radiation Areas of Ramsar, Iran: Preliminary Biological Studies,” Health Physics, Vol. 82, No. 1, 2002, pp. 87-93. doi:10.1097/00004032-200201000-00011
 A. K. Mohanty, D. Sengupta, S. K. Das, V. Vijayan and S. K. Saha, “Natural Radioactivity in the Newly Discovered High Background Radiation Area on the Eastern Coast of Orissa, India,” Radiation Measurements, Vol. 38, No. 2, 2004, pp. 153-165. doi:10.1016/j.radmeas.2003.08.003
 D. C. Vasconcelos, C. Pereira, A. H. Oliveira, T. O. Santos, Z. Rocha and M. A. B. C. Menezes, “Determination of Natural Radioactivity in Beach sand in the Extreme South of Bahia, Brazil, Using Gamma Spectrometry,” Radiation Protection and Environment, Vol. 34, No. 3, 2012, pp. 178-184.
 A. Malarica, C. N. Luce, R. Sogni, L. Achilli and S. Fabbri, “Naturally Occurring Radionuclides in the Monazite Sands of Guarapari and Meaipe (Brazil),” Proceedings of the La Radioattività Ambientale nel Nuovo assetto Istituzionale Piancenza, Bologna and Ravenna, 3 November 1994, pp. 225-230.
 N. Fujinami, T. Koga and H. Morishima, “External Exposure from Terrestrial Radiation at Guarapari and Meaipe in Brazil,” Proceedings of the 10th International Congress of the International Radiation Protection Association, Hiroshima, 14-19 May 2000, pp. 1-19.
 A. C. Freitas and A. S. Alencar, “Gamma Dose Rates and Distribution of Natural Radionuclides in Sand Beaches— Ilha Grande, Southeastern Brazil,” Journal of Environmental Radioactivity, Vol. 75, No. 2, 2004, pp. 211-223. doi:10.1016/j.jenvrad.2004.01.002
 CPRM, “Rio de Janeiro Project. Geological Service of Brazil,” 2012. http://www.cprm.gov.br
 Google Maps, 2012. http://maps.google.com.br/maps
 “The Berkeley Laboratory Isotopes Project’s: Exploring the Table of Isotopes,” 2011. http://ie.lbl.gov/education/isotopes.htm
 “Table of Nuclides: Nuclear Data Services,” 2011. http://www-nds.iaea.org/relnsd/vcharthtml/VChartHTML.html
 P. Chiozzi, V. Pasquale and M. Verdoya, “Naturally Occurring Radioactivity at the Alps-Apennines Transition,” Radiation Measurements, Vol. 35, No. 2, 2002, pp. 147-154. doi:10.1016/S1350-4487(01)00288-8
 National Council on Radiation Protection and Measurements (NCRP), “Exposure of the Population in the United States and Canada from Natural Background Radiation,” NCRP Report No. 94, Maryland, 2011.
 M. R. Abdi, H. Faghihian, M. Kamali, M. Mostajaboddavati and A. Hasanzadeh, “Distribution of Natural Radionuclides on Coasts of Bushehr, Persian Gulf, Iran,” Iranian Journal of Science & Technology, Transaction A, Vol. 30, No. A3, 2006, pp. 259-268.
 A. M. El-Arabi, “Natural Radioactivity in Sand Used in Thermal Therapy at the Red Sea Coast,” Journal of Environmental Radioactivity, Vol. 81, No. 1, 2005, pp. 11-19. doi:10.1016/j.jenvrad.2004.11.002
 M. R. Abdi, M. Kamali and Vaezifar, “Distribution of Radioactive Pollution of 238U, 232Th, 40K and 137Cs in Northwestern Coasts of Persian Gulf, Iran,” Marine Pollution Bulletin, Vol. 56, No. 4, 2008, pp. 751-757. doi:10.1016/j.marpolbul.2007.12.010
 X. Lu and X. Zhang, “Measurement of Natural Radiactivity in Sand Samples Collected from the Baoji Weihe Sands Park, China,” Environmental Geolology, Vol. 50, No. 7, 2006, pp. 977-982. doi:10.1007/s00254-006-0266-5
 X. Lu and X. Zhang, “Measurement of Natural Radioactivity in Beach Sands from Rizhao Bathing Beach, China,” Radiation Protection Dosimetry, Vol. 130, No. 3, 2008, pp. 385-388. doi:10.1093/rpd/ncn053