V. Elisha Ugoma, S. Igbinoba, and K. Imanze, “Effect of Copper Suplementation on Biogas Yield from Co-Digestion of Cattle Dung and Jatropha Curcas Fruit Coat”, FJS, vol. 10, no. 11, pp. 1–7, Jul. 2026, doi: 10.33003/fjs-2026-1011-5194.