Fenty Maimunah Simbolon, Noverina Chaniago, and Joni Pranata Ginting. “RESPONSE OF FROM OIL PALM EMPTY FRUITS AND EM-4 COMPOSTING ON TOP SOIL MEDIA TO VEGETATIVE GROWTH OF COCOA ( Theobroma Cacao L.)”. International Journal of Educational Research Excellence (IJERE), June 2020, pp. 39-45, https://ejournal.ipinternasional.com/index.php/ijere/article/view/657.