Masitah Alias, and Zaini Hamzah, and Ahmad Saat, and Muhamat Omar, and Zakaria Tajuddin, (2005) Determination of 226Ra, 228Ra and 40K in Soil from Felda Jengka-15 Oil Palm Plantation. Malaysian Journal of Analytical Sciences, 9 (1). pp. 126-132. ISSN 1394-2506