Suleiman, A. I., L. W. H. Kevin, and A. S. Ajayi. 2020. “Performance of a Simplified Model Inner-Tube Biodigester for Biomethane Production for Household Use in Nigeria”. ARID ZONE JOURNAL OF ENGINEERING, TECHNOLOGY AND ENVIRONMENT 14 (SP.i4), 168-84. https://azojete.com.ng/index.php/azojete/article/view/263.