Sinaga, Era Pelita. “Expert System for Diagnosing Pests and Diseases in Arabica Coffee Plants Using the Certainty Factor Method”. International Journal of Basic and Applied Science 9, no. 2 (September 30, 2020): 34–37. Accessed May 2, 2026. https://ijobas.pelnus.ac.id/index.php/ijobas/article/view/13.