Waiman, Elina, Anhari Achadi, and Renita Agustina. “REDUCING HOSPITAL OUTPATIENT WAITING TIME USING LEAN SIX SIGMA: A SYSTEMATIC REVIEW”. Indonesian Journal of Health Administration (Jurnal Administrasi Kesehatan Indonesia) 11, no. 1 (June 29, 2023): 154–166. Accessed June 11, 2025. https://e-journal.unair.ac.id/JAKI/article/view/32561.