Sulma Hajijatur Ridlwana, Arifiani Agustin Amalia, and Yeni Rahmawati, “Internal Quality Control Analysis of Sgot and Sgpt Examination Using Levey-Jennings Graphics and Six Sigma at X Hospital Yogyakarta: Analisis Quality Control Internal Pemeriksaan Sgot dan Sgpt Menggunakan Grafik Levey-Jennings dan Six Sigma di RS X Yogyakarta”, JoH, vol. 12, no. 1, pp. 060-068, Jan. 2025.