Abidin, Z. “ENERGY MANAGEMENT HYBRID BIOGAS AND SURYA ENERGY IN ELECTRICAL POWER SUPPLY OF LIVESTOCK INDUSTRY”. Jurnal Ecotipe (Electronic, Control, Telecommunication, Information, and Power Engineering), Vol. 2, no. 2, Oct. 2015, pp. 30-36, doi:10.33019/ecotipe.v2i2.38.