Waiman, E., A. Achadi, and R. Agustina. “REDUCING HOSPITAL OUTPATIENT WAITING TIME USING LEAN SIX SIGMA: A SYSTEMATIC REVIEW”. Indonesian Journal of Health Administration (Jurnal Administrasi Kesehatan Indonesia), vol. 11, no. 1, June 2023, pp. 154-66, doi:10.20473/jaki.v11i1.2023.154-166.