Khoo, V.C. 2019. A Case Study of Return On Investment for Multi-sites Test Handler in The Semiconductor Industry Through Theory of Industry 4.0 ROI Relativity. International Journal of Recent Contributions from Engineering, Science & IT (iJES). 7, 3 (Sep. 2019), pp. 23–40. DOI:https://doi.org/10.3991/ijes.v7i3.11057.