Orugba, Henry Oghenero, et al. “Production of Biodiesel from a Novel Combination of Raphia Africana Kernel Oil and Turtle Shell (Centrochelys Sulcata) Heterogenous Catalyst”. Journal of Human, Earth, and Future, vol. 2, no. 3, Sept. 2021, pp. 258-6, doi:10.28991/HEF-2021-02-03-07.