Ukpene, A. O., O. C. Molua, F. C. Ighrakpata, D. N. Nwachuku, D. A. Ogwu, and M. Edobor. “OPTIMIZATION OF BIOGAS PRODUCTION FROM TREE WASTE MATERIALS FOR BIORESOURCE RECOVERY”. FUDMA JOURNAL OF SCIENCES, vol. 7, no. 6, Dec. 2023, pp. 209 -13, doi:10.33003/fjs-2023-0706-2118.