“Forecasting Shallot Prices in West Sumatra Province Using the Fuzzy Time Series Method of the Singh Model and the Cheng Model”, ujsds, vol. 1, no. 1, hlm. 8–15, Jan 2022, Diakses: Okt 06, 2026. Tersedia pada: https://ujsds.ppj.unp.ac.id/index.php/ujsds/article/view/7