Helmi, Y. R., Y. Yuhandri, and G. W. Nurcahyo. “Expert System in Identifying Promotions for Civil Servants Using the Backward Chaining Method”. Jurnal Informasi Dan Teknologi, Vol. 3, no. 4, Dec. 2021, pp. 190-5, doi:10.37034/jidt.v3i4.149.