Noorhadi, Nur Fatin Nasuha, and Siti Radziah Abdullah. “A Study of Geopolymer Fresh Properties and Mechanical Properties in 3D Concrete Printing”. Recent Trends in Civil Engineering and Built Environment, vol. 3, no. 1, Nov. 2021, pp. 241-9, https://penerbit.uthm.edu.my/periodicals/index.php/rtcebe/article/view/3596.