A. Elzain, Abd-Elmoniem, 		K. Sarn, Adam, 		M. Mukhtar, Othman, AND 		A. Abbasher, Mustafa.
" Measurements of Radon gas Concentration in a Soil at Some Towns in Kassala State" <em>Gezira Journal of Engineering and Applied Sciences</em> [Online], Volume 4 Number 1 (7 September 2009)