B.J., Olawuyi, and Olusola K. O. “Compressive Strength of Volcanic Ash/Ordinary Portland Cement Laterized Concrete”. Civil Engineering Dimension 12, no. 1 (March 5, 2010): 23-28. Accessed April 20, 2024. https://ced.petra.ac.id/index.php/civ/article/view/17898.