EFFECTIVITY IMPROVEMENT OF HYBRID PROJECT MANAGEMENT WATER-SCRUM-FALL WITH SIX SIGMA IMPLEMENTATION. jitk [Internet]. 2024 Aug. 1 [cited 2026 Feb. 11];10(1):124-31. Available from: https://ejournal.nusamandiri.ac.id/ejurnal/index.php/jitk/article/view/5539