Sahay, A.S. et al. 2021. Sistem Pakar Diagnosa Penyakit Lambung Berbasis Website Menggunakan Metode Forward Chaining & Certainty Factor. Journal of Information Technology and Computer Science. 1, 3 (Dec. 2021), 192–201. DOI:https://doi.org/10.47111/jointecoms.v1i3.8813.