Lubis, A. I. ., & Gaol, N. Y. L. . (2022). Application of Certainty Factor Method in Intelligent System for Diagnosis of Periodontal Disease in Cigarette AddictsApplication of Certainty Factor Method in Intelligent System for Diagnosis of Periodontal Disease in Cigarette Addicts. Sinkron : Jurnal Dan Penelitian Teknik Informatika, 6(4), 2272-2279. https://doi.org/10.33395/sinkron.v7i4.11695