How, Meng-Leong, and Chee-Kit Looi. “Using Grey-Based Mathematical Equations of Decision-Making As Teaching Scaffolds: From an Unplugged Computational Thinking Activity to Computer Programming”. International Journal of Computer Science Education in Schools 2, no. 2 (May 17, 2018): 29-46. Accessed July 9, 2020. https://ijcses.org/index.php/ijcses/article/view/24.