Hutasuhut, D.I.G., Ommi Alfina, Nita Syahputri, Sihotang, S.F., Efani Desi and Siti Aliyah 2021. Expert System Detects Boiler Engine Damage Using Certainty Factors. U-NET Jurnal Teknik Informatika. 5, 2 (Aug. 2021), 67-75. DOI:https://doi.org/10.52332/u-net.v5i2.350.