RamijaK. E., SudrajatA., IrwandiH., and AriantonoJ. Y. “Influence of El Niño 2015/2016 on Climate Variability and Production of Main Crops in Langkat Regency”. Agromet, Vol. 35, no. 2, Oct. 2021, pp. 98-107, doi:10.29244/j.agromet.35.2.98-107.