Othman, N., N. S. Jasni, N. R. Rosli, N. H. Yusoff, M. R. Shari, H. Hassan, A. A. Mahmood, A. M. Terry, and N. Abdullah. “Residence Time Distribution (RTD) Model of Water Flooding in Vertical Sand Column Using Technetium-99m As the Radiotracer”. Malaysian Journal of Chemical Engineering &Amp; Technology, vol. 5, no. 2, Oct. 2022, pp. 99-106, doi:10.24191/mjcet.v5i2.19758.