UmarH. A., AbubakarZ., and LimanA. Z. “STUDY INTO THE DRAIN DOWN CHARACTERISTIC OF SMA CONCRETE USING SANDSTONE AS MINERAL FILLER”. FUDMA JOURNAL OF SCIENCES, Vol. 4, no. 1, Apr. 2020, pp. 250 -60, https://fjs.fudutsinma.edu.ng/index.php/fjs/article/view/45.