R. G. D. Libre Jr., L. E. O. Garciano, M. A. B. Promentilla, E. J. Guades, and J. M. C. Ongpeng, “Compressive Strength and Setting Time of Mill Scale-Low Calcium Fly Ash Based Geopolymer Paste”, Chemical Engineering Transactions, vol. 94, pp. 175-180, Sep. 2022.