2021. Study of Key Success Factors for Lean Six Sigma And Last Planner System In Basement Work On High-rise Residential Building Projects, Jakarta Indonesia. International Journal of Engineering Research and Advanced Technology (ijerat) (E-ISSN 2454-6135) DOI: 10.31695/IJERAT. 7, 4 (Apr. 2021), 1–12. DOI:https://doi.org/10.31695/IJERAT.2021.3700.