Matsitsi, S.M. et al. 2019. Effects of Seasonal Change on the Levels of Geogenic Radionuclides in Sand and Rocks from Tyaa River deposit in Kitui County: Geophysics. International Journal of Fundamental Physical Sciences. 9, 1 (Mar. 2019), 14–19. DOI:https://doi.org/10.14331/ijfps.2019.330124.