Mohamed Yusof, Mohamed Khatif Tawaf, Siti Shahidah Sharipudin, Shahrul Nizam Mohammad, Azmi Roslan, Zeno Michael, Ilya Izyan Shahrul Azhar, and Nurrul Amilin Zainal Abidin. “Feasibility Study of Palm Oil Boiler Ash (POBA) As a Partial Replacement of Sand in Foamed Concrete”. Scientific Review Engineering and Environmental Studies (SREES) 31, no. 1 (February 24, 2022): 3–13. Accessed May 17, 2022. https://srees.sggw.edu.pl/article/view/2314.