Sanusi A., Abdulkadir B., and Baki, A.S. “Comparative Study on the Efficacy of Biogas Production from Mixture of Animal Waste and Pistia Stratioles (Water Lettuce)”. UMYU Journal of Microbiology Research (UJMR), vol. 2, no. 2, Dec. 2017, pp. 125-9, doi:10.47430/ujmr.1722.019.