M. Asraf H, N. Md Tahir, N. Dalila K.A., and A. Hussain, “An Agricultural Tele-Monitoring Method in Detecting Nutrient Deficiencies of Oil Palm Leaf”, IJET, vol. 7, no. 4.11, pp. 227–230, Oct. 2018, doi: 10.14419/ijet.v7i4.11.20812.