“Comparison of Breakdown Voltage and Aging of Kraft Paper in Transformers Immersed in Mineral Oil, Natural Ester, and Synthetic Ester”. ENERGY: JURNAL ILMIAH ILMU-ILMU TEKNIK 15, no. 2 (November 30, 2025): 309–323. Accessed February 4, 2026. https://e-journal.upm.ac.id/index.php/energy/article/view/energy.v15i2.15215.