Niko Ramot Saragi, Arnes Sembiring and Nurhayati (2022) “Expert System To Diagnose The Feasibility Of Drinking Water For Consumption Using Certainty Factor Method In Pdam Tirta Sari Kota Binjai”, International Journal of Health Engineering and Technology (IJHET), 1(2). doi: 10.55227/ijhet.v1i2.29.