Kevin Ooi Chin Kai, et al. “Fresh Properties and Flexural Strength of 3D Printing Concrete Containing GGBS With Varies in Water-Cement Ratio”. Journal of Structural Monitoring and Built Environment, vol. 2, no. 1, Dec. 2022, pp. 24-32, https://publisher.uthm.edu.my/ojs/index.php/jsmbe/article/view/12677.